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

#ifndef __NETNS_CORE_H__
#define __NETNS_CORE_H__

struct ctl_table_header;
struct prot_inuse;

struct netns_core {
	/* core sysctls */
	struct ctl_table_header	*sysctl_hdr;

	int	sysctl_somaxconn;

	struct prot_inuse __percpu *inuse;
};

#endif