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 sock;
  14 struct net {
  15         atomic_t                count;          /* To decided when the network
  16                                                  *  namespace should be freed.
  17                                                  */
  18         atomic_t                use_count;      /* To track references we
  19                                                  * destroy on demand
  20                                                  */
  21         struct list_head        list;           /* list of network namespaces */
  22         struct work_struct      work;           /* work struct for freeing */
  23
  24         struct proc_dir_entry   *proc_net;
  25         struct proc_dir_entry   *proc_net_stat;
  26         struct proc_dir_entry   *proc_net_root;
  27
  28         struct net_device       *loopback_dev;          /* The loopback */
  29
  30         struct list_head        dev_base_head;
  31         struct hlist_head       *dev_name_head;
  32         struct hlist_head       *dev_index_head;
  33
  34         struct sock             *rtnl;                  /* rtnetlink socket */
  35
  36         /* List of all packet sockets. */
  37         rwlock_t                packet_sklist_lock;
  38         struct hlist_head       packet_sklist;
  39 };
  40
  41 #ifdef CONFIG_NET
  42 /* Init's network namespace */
  43 extern struct net init_net;
  44 #define INIT_NET_NS(net_ns) .net_ns = &init_net,
  45 #else
  46 #define INIT_NET_NS(net_ns)
  47 #endif
  48
  49 extern struct list_head net_namespace_list;
  50
  51 #ifdef CONFIG_NET
  52 extern struct net *copy_net_ns(unsigned long flags, struct net *net_ns);
  53 #else
  54 static inline struct net *copy_net_ns(unsigned long flags, struct net *net_ns)
  55 {
  56         /* There is nothing to copy so this is a noop */
  57         return net_ns;
  58 }
  59 #endif
  60
  61 #ifdef CONFIG_NET_NS
  62 extern void __put_net(struct net *net);
  63
  64 static inline struct net *get_net(struct net *net)
  65 {
  66         atomic_inc(&net->count);
  67         return net;
  68 }
  69
  70 static inline struct net *maybe_get_net(struct net *net)
  71 {
  72         /* Used when we know struct net exists but we
  73          * aren't guaranteed a previous reference count
  74          * exists.  If the reference count is zero this
  75          * function fails and returns NULL.
  76          */
  77         if (!atomic_inc_not_zero(&net->count))
  78                 net = NULL;
  79         return net;
  80 }
  81
  82 static inline void put_net(struct net *net)
  83 {
  84         if (atomic_dec_and_test(&net->count))
  85                 __put_net(net);
  86 }
  87
  88 static inline struct net *hold_net(struct net *net)
  89 {
  90         atomic_inc(&net->use_count);
  91         return net;
  92 }
  93
  94 static inline void release_net(struct net *net)
  95 {
  96         atomic_dec(&net->use_count);
  97 }
  98 #else
  99 static inline struct net *get_net(struct net *net)
 100 {
 101         return net;
 102 }
 103
 104 static inline void put_net(struct net *net)
 105 {
 106 }
 107
 108 static inline struct net *hold_net(struct net *net)
 109 {
 110         return net;
 111 }
 112
 113 static inline void release_net(struct net *net)
 114 {
 115 }
 116
 117 static inline struct net *maybe_get_net(struct net *net)
 118 {
 119         return net;
 120 }
 121 #endif
 122
 123 #define for_each_net(VAR)                               \
 124         list_for_each_entry(VAR, &net_namespace_list, list)
 125
 126 #ifdef CONFIG_NET_NS
 127 #define __net_init
 128 #define __net_exit
 129 #define __net_initdata
 130 #else
 131 #define __net_init      __init
 132 #define __net_exit      __exit_refok
 133 #define __net_initdata  __initdata
 134 #endif
 135
 136 struct pernet_operations {
 137         struct list_head list;
 138         int (*init)(struct net *net);
 139         void (*exit)(struct net *net);
 140 };
 141
 142 extern int register_pernet_subsys(struct pernet_operations *);
 143 extern void unregister_pernet_subsys(struct pernet_operations *);
 144 extern int register_pernet_device(struct pernet_operations *);
 145 extern void unregister_pernet_device(struct pernet_operations *);
 146
 147 #endif /* __NET_NET_NAMESPACE_H */