From a650a34fc3a424075c48ec9d88b4d77bf1735fe4 Mon Sep 17 00:00:00 2001
From: GnomeZworc <nicolas.boufidjeline@g3e.fr>
Date: Thu, 8 Jan 2026 23:47:52 +0100
Subject: [PATCH] f-10: code: add function to call a function in a netns #10

Signed-off-by: GnomeZworc <nicolas.boufidjeline@g3e.fr>
---
 internal/netns/call.go       |  5 ++++
 internal/netns/call_linux.go | 44 ++++++++++++++++++++++++++++++++++++
 internal/netns/call_other.go |  7 ++++++
 3 files changed, 56 insertions(+)
 create mode 100644 internal/netns/call.go
 create mode 100644 internal/netns/call_linux.go
 create mode 100644 internal/netns/call_other.go

diff --git a/internal/netns/call.go b/internal/netns/call.go
new file mode 100644
index 0000000..da326fd
--- /dev/null
+++ b/internal/netns/call.go
@@ -0,0 +1,5 @@
+package netns
+
+func Call(name string, fn func() error) error {
+	return call(name, fn)
+}
diff --git a/internal/netns/call_linux.go b/internal/netns/call_linux.go
new file mode 100644
index 0000000..b23ac19
--- /dev/null
+++ b/internal/netns/call_linux.go
@@ -0,0 +1,44 @@
+//go:build linux
+
+package netns
+
+import (
+	"fmt"
+	"os"
+	"runtime"
+
+	"golang.org/x/sys/unix"
+)
+
+func call(name string, fn func() error) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	// sauvegarde du netns courant
+	orig, err := os.Open("/proc/self/ns/net")
+	if err != nil {
+		return err
+	}
+	defer orig.Close()
+
+	// entrer dans le netns cible
+	f, err := os.Open(fmt.Sprintf("/var/run/netns/%s", name))
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	if err := unix.Setns(int(f.Fd()), unix.CLONE_NEWNET); err != nil {
+		return err
+	}
+
+	// exécuter la fonction dans le netns
+	err = fn()
+
+	// toujours revenir au netns d'origine
+	if restoreErr := unix.Setns(int(orig.Fd()), unix.CLONE_NEWNET); restoreErr != nil {
+		return restoreErr
+	}
+
+	return err
+}
diff --git a/internal/netns/call_other.go b/internal/netns/call_other.go
new file mode 100644
index 0000000..14a8924
--- /dev/null
+++ b/internal/netns/call_other.go
@@ -0,0 +1,7 @@
+//go:build !linux
+
+package netns
+
+func call(name string, fn func() error) error {
+	return fn()
+}