#include <linux/sched.h>
#include <linux/idr.h>
#include <net/net_namespace.h>
+#include <net/netns/generic.h>
/*
* Our network namespace constructor/destructor lists
struct net init_net;
EXPORT_SYMBOL(init_net);
+#define INITIAL_NET_GEN_PTRS 13 /* +1 for len +2 for rcu_head */
+
/*
* setup_net runs the initializers for the network namespace object.
*/
/* Must be called with net_mutex held */
struct pernet_operations *ops;
int error;
+ struct net_generic *ng;
atomic_set(&net->count, 1);
+#ifdef NETNS_REFCNT_DEBUG
atomic_set(&net->use_count, 0);
+#endif
+
+ error = -ENOMEM;
+ ng = kzalloc(sizeof(struct net_generic) +
+ INITIAL_NET_GEN_PTRS * sizeof(void *), GFP_KERNEL);
+ if (ng == NULL)
+ goto out;
+
+ ng->len = INITIAL_NET_GEN_PTRS;
+ INIT_RCU_HEAD(&ng->rcu);
+ rcu_assign_pointer(net->gen, ng);
error = 0;
list_for_each_entry(ops, &pernet_list, list) {
}
rcu_barrier();
+ kfree(ng);
goto out;
}
if (!net)
return;
+#ifdef NETNS_REFCNT_DEBUG
if (unlikely(atomic_read(&net->use_count) != 0)) {
printk(KERN_EMERG "network namespace not free! Usage: %d\n",
atomic_read(&net->use_count));
return;
}
+#endif
kmem_cache_free(net_cachep, net);
}
struct pernet_operations *ops;
struct net *net;
+ /* Be very certain incoming network packets will not find us */
+ rcu_barrier();
+
net = container_of(work, struct net, work);
mutex_lock(&net_mutex);
mutex_unlock(&net_mutex);
}
EXPORT_SYMBOL_GPL(unregister_pernet_gen_device);
+
+static void net_generic_release(struct rcu_head *rcu)
+{
+ struct net_generic *ng;
+
+ ng = container_of(rcu, struct net_generic, rcu);
+ kfree(ng);
+}
+
+int net_assign_generic(struct net *net, int id, void *data)
+{
+ struct net_generic *ng, *old_ng;
+
+ BUG_ON(!mutex_is_locked(&net_mutex));
+ BUG_ON(id == 0);
+
+ ng = old_ng = net->gen;
+ if (old_ng->len >= id)
+ goto assign;
+
+ ng = kzalloc(sizeof(struct net_generic) +
+ id * sizeof(void *), GFP_KERNEL);
+ if (ng == NULL)
+ return -ENOMEM;
+
+ /*
+ * Some synchronisation notes:
+ *
+ * The net_generic explores the net->gen array inside rcu
+ * read section. Besides once set the net->gen->ptr[x]
+ * pointer never changes (see rules in netns/generic.h).
+ *
+ * That said, we simply duplicate this array and schedule
+ * the old copy for kfree after a grace period.
+ */
+
+ ng->len = id;
+ INIT_RCU_HEAD(&ng->rcu);
+ memcpy(&ng->ptr, &old_ng->ptr, old_ng->len);
+
+ rcu_assign_pointer(net->gen, ng);
+ call_rcu(&old_ng->rcu, net_generic_release);
+assign:
+ ng->ptr[id - 1] = data;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(net_assign_generic);