From c2a318e429c94376ebcc12527a3c3f0ca41dfb6d Mon Sep 17 00:00:00 2001
From: boratanrikulu <me@bora.sh>
Date: Sat, 27 Jul 2024 18:41:31 +0300
Subject: [PATCH] feat: add retry mechanism for attaching eBPF program

---
 internal/ebpf/attach.go | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/internal/ebpf/attach.go b/internal/ebpf/attach.go
index cda454b..712bc86 100644
--- a/internal/ebpf/attach.go
+++ b/internal/ebpf/attach.go
@@ -3,6 +3,7 @@ package ebpf
 import (
 	"fmt"
 	"net"
+	"time"
 
 	"github.com/cilium/ebpf/link"
 )
@@ -14,18 +15,31 @@ var (
 	ErrNoAttach        = fmt.Errorf("not attached to the interface")
 )
 
-// Attach attaches eBPF program to the kernel.
+// Attach attaches the eBPF program to the kernel with retry logic.
 func (e *EBPF) Attach(iface *net.Interface) error {
+	const maxRetries = 3
+	const retryDelay = 100 * time.Millisecond
+
 	if e.L != nil {
 		return fmt.Errorf(
 			"%w: %s", ErrAlreadyAttached, iface.Name,
 		)
 	}
 
-	l, err := link.AttachXDP(link.XDPOptions{
-		Program:   e.Objects.XdpDurdurFunc,
-		Interface: iface.Index,
-	})
+	var l link.Link
+	var err error
+	for i := 0; i < maxRetries; i++ {
+		l, err = link.AttachXDP(link.XDPOptions{
+			Program:   e.Objects.XdpDurdurFunc,
+			Interface: iface.Index,
+		})
+		if err == nil {
+			break
+		}
+		if i < maxRetries-1 {
+			time.Sleep(retryDelay)
+		}
+	}
 	if err != nil {
 		return fmt.Errorf("attach: %w", err)
 	}