Fix namespacing

main.go

@@ -216,26 +216,47 @@ func configureContainerInterface(containerNS netns.NsHandle, ifName string, cont
 		return err
 	}
 
-		// Get host veth link-local address for routing
+	// Switch to main namespace to get host veth address
+	if err := netns.Set(originalNS); err != nil {
+		return err
+	}
+
+	// Get host veth link-local address
 	hostVeth, err := netlink.LinkByName(hostVethName)
-		if err == nil {
+	if err != nil {
+		return err
+	}
+
 	hostAddrs, err := netlink.AddrList(hostVeth, netlink.FAMILY_V6)
-			if err == nil {
+	if err != nil {
+		return err
+	}
+
+	var hostLLAddr net.IP
 	for _, addr := range hostAddrs {
 		if addr.IP.IsLinkLocalUnicast() {
+			hostLLAddr = addr.IP
+			break
+		}
+	}
+
+	// Switch back to container namespace to add route
+	if err := netns.Set(containerNS); err != nil {
+		return err
+	}
+
+	if hostLLAddr != nil {
 		// Add route to Mycelium network via host veth
 		route := &netlink.Route{
 			Dst: &net.IPNet{
 				IP:   net.ParseIP("400::"),
 				Mask: net.CIDRMask(7, 128),
 			},
-							Gw:        addr.IP,
+			Gw:        hostLLAddr,
 			LinkIndex: link.Attrs().Index,
 		}
-						netlink.RouteAdd(route)
-						break
-					}
-				}
+		if err := netlink.RouteAdd(route); err != nil {
+			return err
 		}
 	}