Fix stuff

go.mod

@@ -7,3 +7,5 @@ require (
 	github.com/vishvananda/netlink v1.1.0
 	github.com/vishvananda/netns v0.0.4
 )
+
+require golang.org/x/sys v0.2.0 // indirect

main.go

@@ -4,8 +4,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"net"
-	"os"
-	"path/filepath"
 
 	"github.com/containernetworking/cni/pkg/skel"
 	"github.com/containernetworking/cni/pkg/types"
@@ -185,7 +183,17 @@ func createVethPair(hostName, containerName string) (netlink.Link, netlink.Link,
 }
 
 func configureContainerInterface(containerNS netns.NsHandle, ifName string, containerIP net.IP, hostVethName string) error {
-	return netns.Set(containerNS, func(ns netns.NsHandle) error {
+	// Switch to container namespace
+	originalNS, err := netns.Get()
+	if err != nil {
+		return err
+	}
+	defer originalNS.Close()
+	defer netns.Set(originalNS)
+
+	if err := netns.Set(containerNS); err != nil {
+		return err
+	}
 		// Get the interface
 		link, err := netlink.LinkByName(ifName)
 		if err != nil {
@@ -232,7 +240,6 @@ func configureContainerInterface(containerNS netns.NsHandle, ifName string, cont
 		}
 
 		return nil
-	})
 }
 
 func configureHostInterface(hostVeth netlink.Link, containerIP net.IP) error {