/*
   * 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/sctp.h>
  #include <net/netns/dccp.h>
  #include <net/netns/netfilter.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/nftables.h>
  #include <net/netns/xfrm.h>
  
  struct user_namespace;
  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 user_namespace   *user_ns;	/* Owning user namespace */
  
  	unsigned int		proc_inum;
  
  	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 */
  	int			ifindex;
  	unsigned int		dev_unreg_count;
  
  	/* 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_SCTP) || defined(CONFIG_IP_SCTP_MODULE)
  	struct netns_sctp	sctp;
  #endif
  #if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE)
  	struct netns_dccp	dccp;
  #endif
  #ifdef CONFIG_NETFILTER
  	struct netns_nf		nf;
  	struct netns_xt		xt;
  #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
  	struct netns_ct		ct;
  #endif
  #if defined(CONFIG_NF_TABLES) || defined(CONFIG_NF_TABLES_MODULE)
  	struct netns_nftables	nft;
  #endif
  #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
  	struct netns_nf_frag	nf_frag;
  #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
  #if IS_ENABLED(CONFIG_IP_VS)
  	struct netns_ipvs	*ipvs;
  #endif
  	struct sock		*diag_nlsk;
  	atomic_t		fnhe_genid;
  };
  
  /*
   * ifindex generation is per-net namespace, and loopback is
   * always the 1st device in ns (see net_dev_init), thus any
   * loopback device should get ifindex 1
   */
  
  #define LOOPBACK_IFINDEX	1
  
  #include <linux/seq_file_net.h>
  
  /* Init's network namespace */
  extern struct net init_net;
  
  #ifdef CONFIG_NET_NS
  struct net *copy_net_ns(unsigned long flags, struct user_namespace *user_ns,
  			struct net *old_net);
  
  #else /* CONFIG_NET_NS */
  #include <linux/sched.h>
  #include <linux/nsproxy.h>
  static inline struct net *copy_net_ns(unsigned long flags,
  	struct user_namespace *user_ns, struct net *old_net)
  {
  	if (flags & CLONE_NEWNET)
  		return ERR_PTR(-EINVAL);
  	return old_net;
  }
  #endif /* CONFIG_NET_NS */
  
  
  extern struct list_head net_namespace_list;
  
  struct net *get_net_ns_by_pid(pid_t pid);
  struct net *get_net_ns_by_fd(int pid);
  
  #ifdef CONFIG_SYSCTL
  void ipx_register_sysctl(void);
  void ipx_unregister_sysctl(void);
  #else
  #define ipx_register_sysctl()
  #define ipx_unregister_sysctl()
  #endif
  
  #ifdef CONFIG_NET_NS
  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;
  }
  
  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
  #define __net_initconst
  #else
  #define __net_init	__init
  #define __net_exit	__exit_refok
  #define __net_initdata	__initdata
  #define __net_initconst	__initconst
  #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.
   */
  int register_pernet_subsys(struct pernet_operations *);
  void unregister_pernet_subsys(struct pernet_operations *);
  int register_pernet_device(struct pernet_operations *);
  void unregister_pernet_device(struct pernet_operations *);
  
  struct ctl_table;
  struct ctl_table_header;
  
  #ifdef CONFIG_SYSCTL
  int net_sysctl_init(void);
  struct ctl_table_header *register_net_sysctl(struct net *net, const char *path,
  					     struct ctl_table *table);
  void unregister_net_sysctl_table(struct ctl_table_header *header);
  #else
  static inline int net_sysctl_init(void) { return 0; }
  static inline struct ctl_table_header *register_net_sysctl(struct net *net,
  	const char *path, struct ctl_table *table)
  {
  	return NULL;
  }
  static inline void unregister_net_sysctl_table(struct ctl_table_header *header)
  {
  }
  #endif
  
  static inline int rt_genid_ipv4(struct net *net)
  {
  	return atomic_read(&net->ipv4.rt_genid);
  }
  
  static inline void rt_genid_bump_ipv4(struct net *net)
  {
  	atomic_inc(&net->ipv4.rt_genid);
  }
  
  #if IS_ENABLED(CONFIG_IPV6)
  static inline int rt_genid_ipv6(struct net *net)
  {
  	return atomic_read(&net->ipv6.rt_genid);
  }
  
  static inline void rt_genid_bump_ipv6(struct net *net)
  {
  	atomic_inc(&net->ipv6.rt_genid);
  }
  #else
  static inline int rt_genid_ipv6(struct net *net)
  {
  	return 0;
  }
  
  static inline void rt_genid_bump_ipv6(struct net *net)
  {
  }
  #endif
  
  /* For callers who don't really care about whether it's IPv4 or IPv6 */
  static inline void rt_genid_bump_all(struct net *net)
  {
  	rt_genid_bump_ipv4(net);
  	rt_genid_bump_ipv6(net);
  }
  
  static inline int fnhe_genid(struct net *net)
  {
  	return atomic_read(&net->fnhe_genid);
  }
  
  static inline void fnhe_genid_bump(struct net *net)
  {
  	atomic_inc(&net->fnhe_genid);
  }
  
  #endif /* __NET_NET_NAMESPACE_H */