1. 根目录:
2. include
3. net
4. netns
5. netfilter.h

#ifndef __NETNS_NETFILTER_H
#define __NETNS_NETFILTER_H

#include <linux/proc_fs.h>
#include <linux/netfilter.h>

struct nf_logger;

struct netns_nf {
#if defined CONFIG_PROC_FS
	struct proc_dir_entry *proc_netfilter;
#endif
	const struct nf_logger __rcu *nf_loggers[NFPROTO_NUMPROTO];
#ifdef CONFIG_SYSCTL
	struct ctl_table_header *nf_log_dir_header;
#endif
};
#endif