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 #include <net/netns/unix.h>
  12
  13 struct proc_dir_entry;
  14 struct net_device;
  15 struct sock;
  16 struct ctl_table_header;
  17
  18 struct net {
  19         atomic_t                count;          /* To decided when the network
  20                                                  *  namespace should be freed.
  21                                                  */
  22         atomic_t                use_count;      /* To track references we
  23                                                  * destroy on demand
  24                                                  */
  25         struct list_head        list;           /* list of network namespaces */
  26         struct work_struct      work;           /* work struct for freeing */
  27
  28         struct proc_dir_entry   *proc_net;
  29         struct proc_dir_entry   *proc_net_stat;
  30         struct proc_dir_entry   *proc_net_root;
  31
  32         struct list_head        sysctl_table_headers;
  33
  34         struct net_device       *loopback_dev;          /* The loopback */
  35
  36         struct list_head        dev_base_head;
  37         struct hlist_head       *dev_name_head;
  38         struct hlist_head       *dev_index_head;
  39
  40         struct sock             *rtnl;                  /* rtnetlink socket */
  41
  42         /* core sysctls */
  43         struct ctl_table_header *sysctl_core_hdr;
  44         int                     sysctl_somaxconn;
  45
  46         /* List of all packet sockets. */
  47         rwlock_t                packet_sklist_lock;
  48         struct hlist_head       packet_sklist;
  49
  50         struct netns_unix       unx;
  51 };
  52
  53 #ifdef CONFIG_NET
  54 /* Init's network namespace */
  55 extern struct net init_net;
  56 #define INIT_NET_NS(net_ns) .net_ns = &init_net,
  57 #else
  58 #define INIT_NET_NS(net_ns)
  59 #endif
  60
  61 extern struct list_head net_namespace_list;
  62
  63 #ifdef CONFIG_NET
  64 extern struct net *copy_net_ns(unsigned long flags, struct net *net_ns);
  65 #else
  66 static inline struct net *copy_net_ns(unsigned long flags, struct net *net_ns)
  67 {
  68         /* There is nothing to copy so this is a noop */
  69         return net_ns;
  70 }
  71 #endif
  72
  73 #ifdef CONFIG_NET_NS
  74 extern void __put_net(struct net *net);
  75
  76 static inline struct net *get_net(struct net *net)
  77 {
  78         atomic_inc(&net->count);
  79         return net;
  80 }
  81
  82 static inline struct net *maybe_get_net(struct net *net)
  83 {
  84         /* Used when we know struct net exists but we
  85          * aren't guaranteed a previous reference count
  86          * exists.  If the reference count is zero this
  87          * function fails and returns NULL.
  88          */
  89         if (!atomic_inc_not_zero(&net->count))
  90                 net = NULL;
  91         return net;
  92 }
  93
  94 static inline void put_net(struct net *net)
  95 {
  96         if (atomic_dec_and_test(&net->count))
  97                 __put_net(net);
  98 }
  99
 100 static inline struct net *hold_net(struct net *net)
 101 {
 102         atomic_inc(&net->use_count);
 103         return net;
 104 }
 105
 106 static inline void release_net(struct net *net)
 107 {
 108         atomic_dec(&net->use_count);
 109 }
 110 #else
 111 static inline struct net *get_net(struct net *net)
 112 {
 113         return net;
 114 }
 115
 116 static inline void put_net(struct net *net)
 117 {
 118 }
 119
 120 static inline struct net *hold_net(struct net *net)
 121 {
 122         return net;
 123 }
 124
 125 static inline void release_net(struct net *net)
 126 {
 127 }
 128
 129 static inline struct net *maybe_get_net(struct net *net)
 130 {
 131         return net;
 132 }
 133 #endif
 134
 135 #define for_each_net(VAR)                               \
 136         list_for_each_entry(VAR, &net_namespace_list, list)
 137
 138 #ifdef CONFIG_NET_NS
 139 #define __net_init
 140 #define __net_exit
 141 #define __net_initdata
 142 #else
 143 #define __net_init      __init
 144 #define __net_exit      __exit_refok
 145 #define __net_initdata  __initdata
 146 #endif
 147
 148 struct pernet_operations {
 149         struct list_head list;
 150         int (*init)(struct net *net);
 151         void (*exit)(struct net *net);
 152 };
 153
 154 extern int register_pernet_subsys(struct pernet_operations *);
 155 extern void unregister_pernet_subsys(struct pernet_operations *);
 156 extern int register_pernet_device(struct pernet_operations *);
 157 extern void unregister_pernet_device(struct pernet_operations *);
 158
 159 struct ctl_path;
 160 struct ctl_table;
 161 struct ctl_table_header;
 162 extern struct ctl_table_header *register_net_sysctl_table(struct net *net,
 163         const struct ctl_path *path, struct ctl_table *table);
 164 extern void unregister_net_sysctl_table(struct ctl_table_header *header);
 165
 166 #endif /* __NET_NET_NAMESPACE_H */