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_device;
  13 struct net {
  14         atomic_t                count;          /* To decided when the network
  15                                                  *  namespace should be freed.
  16                                                  */
  17         atomic_t                use_count;      /* To track references we
  18                                                  * destroy on demand
  19                                                  */
  20         struct list_head        list;           /* list of network namespaces */
  21         struct work_struct      work;           /* work struct for freeing */
  22
  23         struct proc_dir_entry   *proc_net;
  24         struct proc_dir_entry   *proc_net_stat;
  25         struct proc_dir_entry   *proc_net_root;
  26
  27         struct net_device       *loopback_dev;          /* The loopback */
  28
  29         struct list_head        dev_base_head;
  30         struct hlist_head       *dev_name_head;
  31         struct hlist_head       *dev_index_head;
  32 };
  33
  34 #ifdef CONFIG_NET
  35 /* Init's network namespace */
  36 extern struct net init_net;
  37 #define INIT_NET_NS(net_ns) .net_ns = &init_net,
  38 #else
  39 #define INIT_NET_NS(net_ns)
  40 #endif
  41
  42 extern struct list_head net_namespace_list;
  43
  44 #ifdef CONFIG_NET
  45 extern struct net *copy_net_ns(unsigned long flags, struct net *net_ns);
  46 #else
  47 static inline struct net *copy_net_ns(unsigned long flags, struct net *net_ns)
  48 {
  49         /* There is nothing to copy so this is a noop */
  50         return net_ns;
  51 }
  52 #endif
  53
  54 #ifdef CONFIG_NET_NS
  55 extern void __put_net(struct net *net);
  56
  57 static inline struct net *get_net(struct net *net)
  58 {
  59         atomic_inc(&net->count);
  60         return net;
  61 }
  62
  63 static inline struct net *maybe_get_net(struct net *net)
  64 {
  65         /* Used when we know struct net exists but we
  66          * aren't guaranteed a previous reference count
  67          * exists.  If the reference count is zero this
  68          * function fails and returns NULL.
  69          */
  70         if (!atomic_inc_not_zero(&net->count))
  71                 net = NULL;
  72         return net;
  73 }
  74
  75 static inline void put_net(struct net *net)
  76 {
  77         if (atomic_dec_and_test(&net->count))
  78                 __put_net(net);
  79 }
  80
  81 static inline struct net *hold_net(struct net *net)
  82 {
  83         atomic_inc(&net->use_count);
  84         return net;
  85 }
  86
  87 static inline void release_net(struct net *net)
  88 {
  89         atomic_dec(&net->use_count);
  90 }
  91 #else
  92 static inline struct net *get_net(struct net *net)
  93 {
  94         return net;
  95 }
  96
  97 static inline void put_net(struct net *net)
  98 {
  99 }
 100
 101 static inline struct net *hold_net(struct net *net)
 102 {
 103         return net;
 104 }
 105
 106 static inline void release_net(struct net *net)
 107 {
 108 }
 109
 110 static inline struct net *maybe_get_net(struct net *net)
 111 {
 112         return net;
 113 }
 114 #endif
 115
 116 #define for_each_net(VAR)                               \
 117         list_for_each_entry(VAR, &net_namespace_list, list)
 118
 119 #ifdef CONFIG_NET_NS
 120 #define __net_init
 121 #define __net_exit
 122 #else
 123 #define __net_init      __init
 124 #define __net_exit      __exit_refok
 125 #endif
 126
 127 struct pernet_operations {
 128         struct list_head list;
 129         int (*init)(struct net *net);
 130         void (*exit)(struct net *net);
 131 };
 132
 133 extern int register_pernet_subsys(struct pernet_operations *);
 134 extern void unregister_pernet_subsys(struct pernet_operations *);
 135 extern int register_pernet_device(struct pernet_operations *);
 136 extern void unregister_pernet_device(struct pernet_operations *);
 137
 138 #endif /* __NET_NET_NAMESPACE_H */