include/net/net_namespace.h

   1 /*
   2  * Operations on the network namespace
   3  */
   4 #ifndef __NET_NET_NAMESPACE_H
   5 #define __NET_NET_NAMESPACE_H
   6
   7 #include <asm/atomic.h>
   8 #include <linux/workqueue.h>
   9 #include <linux/list.h>
  10
  11 struct proc_dir_entry;
  12 struct net {
  13         atomic_t                count;          /* To decided when the network
  14                                                  *  namespace should be freed.
  15                                                  */
  16         atomic_t                use_count;      /* To track references we
  17                                                  * destroy on demand
  18                                                  */
  19         struct list_head        list;           /* list of network namespaces */
  20         struct work_struct      work;           /* work struct for freeing */
  21
  22         struct proc_dir_entry   *proc_net;
  23         struct proc_dir_entry   *proc_net_stat;
  24         struct proc_dir_entry   *proc_net_root;
  25
  26         struct list_head        dev_base_head;
  27         struct hlist_head       *dev_name_head;
  28         struct hlist_head       *dev_index_head;
  29 };
  30
  31 #ifdef CONFIG_NET
  32 /* Init's network namespace */
  33 extern struct net init_net;
  34 #define INIT_NET_NS(net_ns) .net_ns = &init_net,
  35 #else
  36 #define INIT_NET_NS(net_ns)
  37 #endif
  38
  39 extern struct list_head net_namespace_list;
  40
  41 extern void __put_net(struct net *net);
  42
  43 static inline struct net *get_net(struct net *net)
  44 {
  45         atomic_inc(&net->count);
  46         return net;
  47 }
  48
  49 static inline struct net *maybe_get_net(struct net *net)
  50 {
  51         /* Used when we know struct net exists but we
  52          * aren't guaranteed a previous reference count
  53          * exists.  If the reference count is zero this
  54          * function fails and returns NULL.
  55          */
  56         if (!atomic_inc_not_zero(&net->count))
  57                 net = NULL;
  58         return net;
  59 }
  60
  61 static inline void put_net(struct net *net)
  62 {
  63         if (atomic_dec_and_test(&net->count))
  64                 __put_net(net);
  65 }
  66
  67 static inline struct net *hold_net(struct net *net)
  68 {
  69         atomic_inc(&net->use_count);
  70         return net;
  71 }
  72
  73 static inline void release_net(struct net *net)
  74 {
  75         atomic_dec(&net->use_count);
  76 }
  77
  78 extern void net_lock(void);
  79 extern void net_unlock(void);
  80
  81 #define for_each_net(VAR)                               \
  82         list_for_each_entry(VAR, &net_namespace_list, list)
  83
  84
  85 struct pernet_operations {
  86         struct list_head list;
  87         int (*init)(struct net *net);
  88         void (*exit)(struct net *net);
  89 };
  90
  91 extern int register_pernet_subsys(struct pernet_operations *);
  92 extern void unregister_pernet_subsys(struct pernet_operations *);
  93 extern int register_pernet_device(struct pernet_operations *);
  94 extern void unregister_pernet_device(struct pernet_operations *);
  95
  96 #endif /* __NET_NET_NAMESPACE_H */