# Re: \[PATCH 5/5\] netfilter: implement xt\_cgroup2 match

- From: Jan Engelhardt \<hidden\>
- Date: 2015-11-17 22:56:05 
- List: netdev
- Page: https://ratatoskr.run/netdev/2015/11/4622797
- Thread: https://ratatoskr.run/netdev/2015/11/4622696/t.md

```text

On Tuesday 2015-11-17 20:40, Tejun Heo wrote:
>@@ -0,0 +1,14 @@
>+#ifndef _XT_CGROUP2_H
>+#define _XT_CGROUP2_H
>+
>+#include <linux/types.h>
>+
>+struct xt_cgroup2_info {
>+	char				path[PATH_MAX];
>+	__u8				invert;

Should <linux/limits.h> be included? (For PATH_MAX)

>+	/* kernel internal data */
>+	void				*priv;
>+};

void *priv __attribute__((aligned(8)));

>+static bool cgroup2_mt(const struct sk_buff *skb, struct xt_action_param *par)
>+{
>+	const struct xt_cgroup2_info *info = par->matchinfo;
>+	struct cgroup *ancestor = info->priv;

There is no modification planned on the cgroup, so this too can be const struct
cgroup * if-and-when cgroup_is_descendant is made to take const ptrs as well.

>+	if (!skb->sk || !sk_fullsock(skb->sk))
>+		return false;
>+
>+	return cgroup_is_descendant(skb->sk->sk_cgroup, ancestor) ^ info->invert;
>+}
```