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-rw-r--r--kernel/include/net/netns/generic.h46
1 files changed, 46 insertions, 0 deletions
diff --git a/kernel/include/net/netns/generic.h b/kernel/include/net/netns/generic.h
new file mode 100644
index 000000000..70e158551
--- /dev/null
+++ b/kernel/include/net/netns/generic.h
@@ -0,0 +1,46 @@
+/*
+ * generic net pointers
+ */
+
+#ifndef __NET_GENERIC_H__
+#define __NET_GENERIC_H__
+
+#include <linux/bug.h>
+#include <linux/rcupdate.h>
+
+/*
+ * Generic net pointers are to be used by modules to put some private
+ * stuff on the struct net without explicit struct net modification
+ *
+ * The rules are simple:
+ * 1. set pernet_operations->id. After register_pernet_device you
+ * will have the id of your private pointer.
+ * 2. set pernet_operations->size to have the code allocate and free
+ * a private structure pointed to from struct net.
+ * 3. do not change this pointer while the net is alive;
+ * 4. do not try to have any private reference on the net_generic object.
+ *
+ * After accomplishing all of the above, the private pointer can be
+ * accessed with the net_generic() call.
+ */
+
+struct net_generic {
+ unsigned int len;
+ struct rcu_head rcu;
+
+ void *ptr[0];
+};
+
+static inline void *net_generic(const struct net *net, int id)
+{
+ struct net_generic *ng;
+ void *ptr;
+
+ rcu_read_lock();
+ ng = rcu_dereference(net->gen);
+ ptr = ng->ptr[id - 1];
+ rcu_read_unlock();
+
+ return ptr;
+}
+#endif