/*
   * Operations on the network namespace
   */
  #ifndef __NET_NET_NAMESPACE_H
  #define __NET_NET_NAMESPACE_H

  #include <linux/atomic.h>

  #include <linux/workqueue.h>
  #include <linux/list.h>

  #include <linux/sysctl.h>

  #include <net/netns/core.h>

  #include <net/netns/mib.h>

  #include <net/netns/unix.h>

  #include <net/netns/packet.h>

  #include <net/netns/ipv4.h>

  #include <net/netns/ipv6.h>

  #include <net/netns/dccp.h>

  #include <net/netns/x_tables.h>

  #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
  #include <net/netns/conntrack.h>
  #endif

  #include <net/netns/xfrm.h>

  struct proc_dir_entry;

  struct net_device;

  struct sock;

  struct ctl_table_header;

  struct net_generic;

  struct sock;

  struct netns_ipvs;

  
  #define NETDEV_HASHBITS    8
  #define NETDEV_HASHENTRIES (1 << NETDEV_HASHBITS)

  struct net {

  	atomic_t		passive;	/* To decided when the network
  						 * namespace should be freed.
  						 */

  	atomic_t		count;		/* To decided when the network

  						 *  namespace should be shut down.

  						 */

  #ifdef NETNS_REFCNT_DEBUG

  	atomic_t		use_count;	/* To track references we
  						 * destroy on demand
  						 */

  #endif

  	spinlock_t		rules_mod_lock;

  	struct list_head	list;		/* list of network namespaces */

  	struct list_head	cleanup_list;	/* namespaces on death row */

  	struct list_head	exit_list;	/* Use only net_mutex */

  
  	struct proc_dir_entry 	*proc_net;
  	struct proc_dir_entry 	*proc_net_stat;

  #ifdef CONFIG_SYSCTL
  	struct ctl_table_set	sysctls;
  #endif

  	struct sock 		*rtnl;			/* rtnetlink socket */
  	struct sock		*genl_sock;

  	struct list_head 	dev_base_head;
  	struct hlist_head 	*dev_name_head;
  	struct hlist_head	*dev_index_head;

  	unsigned int		dev_base_seq;	/* protected by rtnl_mutex */

  	/* core fib_rules */
  	struct list_head	rules_ops;

  	struct net_device       *loopback_dev;          /* The loopback */

  	struct netns_core	core;

  	struct netns_mib	mib;

  	struct netns_packet	packet;

  	struct netns_unix	unx;

  	struct netns_ipv4	ipv4;

  #if IS_ENABLED(CONFIG_IPV6)

  	struct netns_ipv6	ipv6;
  #endif

  #if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE)
  	struct netns_dccp	dccp;
  #endif

  #ifdef CONFIG_NETFILTER
  	struct netns_xt		xt;

  #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
  	struct netns_ct		ct;
  #endif

  	struct sock		*nfnl;
  	struct sock		*nfnl_stash;

  #endif

  #ifdef CONFIG_WEXT_CORE

  	struct sk_buff_head	wext_nlevents;
  #endif

  	struct net_generic __rcu	*gen;

  
  	/* Note : following structs are cache line aligned */
  #ifdef CONFIG_XFRM
  	struct netns_xfrm	xfrm;
  #endif

  	struct netns_ipvs	*ipvs;

  };

  #include <linux/seq_file_net.h>

  /* Init's network namespace */

  extern struct net init_net;

  
  #ifdef CONFIG_NET

  extern struct net *copy_net_ns(unsigned long flags, struct net *net_ns);

  
  #else /* CONFIG_NET */

  static inline struct net *copy_net_ns(unsigned long flags, struct net *net_ns)
  {
  	/* There is nothing to copy so this is a noop */
  	return net_ns;
  }

  #endif /* CONFIG_NET */
  
  
  extern struct list_head net_namespace_list;

  extern struct net *get_net_ns_by_pid(pid_t pid);

  extern struct net *get_net_ns_by_fd(int pid);

  #ifdef CONFIG_NET_NS

  extern void __put_net(struct net *net);
  
  static inline struct net *get_net(struct net *net)
  {
  	atomic_inc(&net->count);
  	return net;
  }

  static inline struct net *maybe_get_net(struct net *net)
  {
  	/* Used when we know struct net exists but we
  	 * aren't guaranteed a previous reference count
  	 * exists.  If the reference count is zero this
  	 * function fails and returns NULL.
  	 */
  	if (!atomic_inc_not_zero(&net->count))
  		net = NULL;
  	return net;
  }

  static inline void put_net(struct net *net)
  {
  	if (atomic_dec_and_test(&net->count))
  		__put_net(net);
  }

  static inline
  int net_eq(const struct net *net1, const struct net *net2)
  {
  	return net1 == net2;
  }

  
  extern void net_drop_ns(void *);

  #else

  static inline struct net *get_net(struct net *net)
  {
  	return net;
  }
  
  static inline void put_net(struct net *net)
  {
  }

  static inline struct net *maybe_get_net(struct net *net)
  {
  	return net;
  }
  
  static inline
  int net_eq(const struct net *net1, const struct net *net2)
  {
  	return 1;
  }

  
  #define net_drop_ns NULL

  #endif
  
  
  #ifdef NETNS_REFCNT_DEBUG

  static inline struct net *hold_net(struct net *net)
  {

  	if (net)
  		atomic_inc(&net->use_count);

  	return net;
  }
  
  static inline void release_net(struct net *net)
  {

  	if (net)
  		atomic_dec(&net->use_count);

  }

  #else
  static inline struct net *hold_net(struct net *net)

  {
  	return net;
  }

  static inline void release_net(struct net *net)

  {

  }

  #endif

  #ifdef CONFIG_NET_NS
  
  static inline void write_pnet(struct net **pnet, struct net *net)
  {
  	*pnet = net;
  }
  
  static inline struct net *read_pnet(struct net * const *pnet)
  {
  	return *pnet;
  }
  
  #else
  
  #define write_pnet(pnet, net)	do { (void)(net);} while (0)
  #define read_pnet(pnet)		(&init_net)
  
  #endif

  #define for_each_net(VAR)				\
  	list_for_each_entry(VAR, &net_namespace_list, list)

  #define for_each_net_rcu(VAR)				\
  	list_for_each_entry_rcu(VAR, &net_namespace_list, list)

  #ifdef CONFIG_NET_NS
  #define __net_init
  #define __net_exit

  #define __net_initdata

  #else
  #define __net_init	__init
  #define __net_exit	__exit_refok

  #define __net_initdata	__initdata

  #endif

  
  struct pernet_operations {
  	struct list_head list;
  	int (*init)(struct net *net);
  	void (*exit)(struct net *net);

  	void (*exit_batch)(struct list_head *net_exit_list);

  	int *id;
  	size_t size;

  };

  /*
   * Use these carefully.  If you implement a network device and it
   * needs per network namespace operations use device pernet operations,
   * otherwise use pernet subsys operations.
   *

   * Network interfaces need to be removed from a dying netns _before_
   * subsys notifiers can be called, as most of the network code cleanup
   * (which is done from subsys notifiers) runs with the assumption that
   * dev_remove_pack has been called so no new packets will arrive during
   * and after the cleanup functions have been called.  dev_remove_pack
   * is not per namespace so instead the guarantee of no more packets
   * arriving in a network namespace is provided by ensuring that all
   * network devices and all sockets have left the network namespace
   * before the cleanup methods are called.

   *
   * For the longest time the ipv4 icmp code was registered as a pernet
   * device which caused kernel oops, and panics during network
   * namespace cleanup.   So please don't get this wrong.
   */

  extern int register_pernet_subsys(struct pernet_operations *);
  extern void unregister_pernet_subsys(struct pernet_operations *);
  extern int register_pernet_device(struct pernet_operations *);
  extern void unregister_pernet_device(struct pernet_operations *);

  struct ctl_path;
  struct ctl_table;
  struct ctl_table_header;

  extern struct ctl_table_header *register_net_sysctl_table(struct net *net,
  	const struct ctl_path *path, struct ctl_table *table);

  extern struct ctl_table_header *register_net_sysctl_rotable(
  	const struct ctl_path *path, struct ctl_table *table);

  extern void unregister_net_sysctl_table(struct ctl_table_header *header);

  #endif /* __NET_NET_NAMESPACE_H */