295 lines
7.0 KiB
C
295 lines
7.0 KiB
C
#include <linux/workqueue.h>
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#include <linux/rtnetlink.h>
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#include <linux/cache.h>
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#include <linux/slab.h>
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#include <linux/list.h>
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#include <linux/delay.h>
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#include <net/net_namespace.h>
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/*
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* Our network namespace constructor/destructor lists
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*/
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static LIST_HEAD(pernet_list);
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static struct list_head *first_device = &pernet_list;
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static DEFINE_MUTEX(net_mutex);
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static DEFINE_MUTEX(net_list_mutex);
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LIST_HEAD(net_namespace_list);
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static struct kmem_cache *net_cachep;
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struct net init_net;
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EXPORT_SYMBOL_GPL(init_net);
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void net_lock(void)
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{
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mutex_lock(&net_list_mutex);
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}
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void net_unlock(void)
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{
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mutex_unlock(&net_list_mutex);
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}
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#if 0
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static struct net *net_alloc(void)
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{
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return kmem_cache_alloc(net_cachep, GFP_KERNEL);
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}
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#endif
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static void net_free(struct net *net)
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{
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if (!net)
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return;
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if (unlikely(atomic_read(&net->use_count) != 0)) {
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printk(KERN_EMERG "network namespace not free! Usage: %d\n",
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atomic_read(&net->use_count));
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return;
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}
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kmem_cache_free(net_cachep, net);
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}
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static void cleanup_net(struct work_struct *work)
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{
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struct pernet_operations *ops;
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struct list_head *ptr;
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struct net *net;
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net = container_of(work, struct net, work);
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mutex_lock(&net_mutex);
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/* Don't let anyone else find us. */
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net_lock();
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list_del(&net->list);
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net_unlock();
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/* Run all of the network namespace exit methods */
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list_for_each_prev(ptr, &pernet_list) {
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ops = list_entry(ptr, struct pernet_operations, list);
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if (ops->exit)
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ops->exit(net);
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}
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mutex_unlock(&net_mutex);
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/* Ensure there are no outstanding rcu callbacks using this
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* network namespace.
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*/
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rcu_barrier();
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/* Finally it is safe to free my network namespace structure */
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net_free(net);
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}
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void __put_net(struct net *net)
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{
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/* Cleanup the network namespace in process context */
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INIT_WORK(&net->work, cleanup_net);
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schedule_work(&net->work);
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}
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EXPORT_SYMBOL_GPL(__put_net);
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/*
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* setup_net runs the initializers for the network namespace object.
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*/
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static int setup_net(struct net *net)
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{
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/* Must be called with net_mutex held */
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struct pernet_operations *ops;
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struct list_head *ptr;
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int error;
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memset(net, 0, sizeof(struct net));
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atomic_set(&net->count, 1);
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atomic_set(&net->use_count, 0);
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error = 0;
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list_for_each(ptr, &pernet_list) {
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ops = list_entry(ptr, struct pernet_operations, list);
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if (ops->init) {
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error = ops->init(net);
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if (error < 0)
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goto out_undo;
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}
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}
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out:
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return error;
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out_undo:
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/* Walk through the list backwards calling the exit functions
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* for the pernet modules whose init functions did not fail.
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*/
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for (ptr = ptr->prev; ptr != &pernet_list; ptr = ptr->prev) {
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ops = list_entry(ptr, struct pernet_operations, list);
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if (ops->exit)
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ops->exit(net);
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}
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goto out;
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}
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static int __init net_ns_init(void)
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{
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int err;
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printk(KERN_INFO "net_namespace: %zd bytes\n", sizeof(struct net));
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net_cachep = kmem_cache_create("net_namespace", sizeof(struct net),
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SMP_CACHE_BYTES,
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SLAB_PANIC, NULL);
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mutex_lock(&net_mutex);
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err = setup_net(&init_net);
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net_lock();
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list_add_tail(&init_net.list, &net_namespace_list);
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net_unlock();
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mutex_unlock(&net_mutex);
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if (err)
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panic("Could not setup the initial network namespace");
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return 0;
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}
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pure_initcall(net_ns_init);
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static int register_pernet_operations(struct list_head *list,
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struct pernet_operations *ops)
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{
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struct net *net, *undo_net;
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int error;
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error = 0;
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list_add_tail(&ops->list, list);
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for_each_net(net) {
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if (ops->init) {
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error = ops->init(net);
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if (error)
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goto out_undo;
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}
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}
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out:
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return error;
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out_undo:
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/* If I have an error cleanup all namespaces I initialized */
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list_del(&ops->list);
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for_each_net(undo_net) {
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if (undo_net == net)
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goto undone;
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if (ops->exit)
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ops->exit(undo_net);
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}
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undone:
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goto out;
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}
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static void unregister_pernet_operations(struct pernet_operations *ops)
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{
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struct net *net;
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list_del(&ops->list);
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for_each_net(net)
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if (ops->exit)
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ops->exit(net);
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}
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/**
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* register_pernet_subsys - register a network namespace subsystem
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* @ops: pernet operations structure for the subsystem
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*
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* Register a subsystem which has init and exit functions
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* that are called when network namespaces are created and
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* destroyed respectively.
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*
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* When registered all network namespace init functions are
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* called for every existing network namespace. Allowing kernel
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* modules to have a race free view of the set of network namespaces.
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*
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* When a new network namespace is created all of the init
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* methods are called in the order in which they were registered.
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*
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* When a network namespace is destroyed all of the exit methods
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* are called in the reverse of the order with which they were
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* registered.
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*/
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int register_pernet_subsys(struct pernet_operations *ops)
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{
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int error;
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mutex_lock(&net_mutex);
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error = register_pernet_operations(first_device, ops);
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mutex_unlock(&net_mutex);
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return error;
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}
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EXPORT_SYMBOL_GPL(register_pernet_subsys);
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/**
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* unregister_pernet_subsys - unregister a network namespace subsystem
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* @ops: pernet operations structure to manipulate
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*
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* Remove the pernet operations structure from the list to be
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* used when network namespaces are created or destoryed. In
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* addition run the exit method for all existing network
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* namespaces.
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*/
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void unregister_pernet_subsys(struct pernet_operations *module)
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{
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mutex_lock(&net_mutex);
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unregister_pernet_operations(module);
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mutex_unlock(&net_mutex);
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}
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EXPORT_SYMBOL_GPL(unregister_pernet_subsys);
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/**
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* register_pernet_device - register a network namespace device
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* @ops: pernet operations structure for the subsystem
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*
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* Register a device which has init and exit functions
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* that are called when network namespaces are created and
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* destroyed respectively.
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*
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* When registered all network namespace init functions are
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* called for every existing network namespace. Allowing kernel
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* modules to have a race free view of the set of network namespaces.
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*
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* When a new network namespace is created all of the init
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* methods are called in the order in which they were registered.
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*
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* When a network namespace is destroyed all of the exit methods
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* are called in the reverse of the order with which they were
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* registered.
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*/
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int register_pernet_device(struct pernet_operations *ops)
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{
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int error;
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mutex_lock(&net_mutex);
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error = register_pernet_operations(&pernet_list, ops);
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if (!error && (first_device == &pernet_list))
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first_device = &ops->list;
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mutex_unlock(&net_mutex);
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return error;
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}
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EXPORT_SYMBOL_GPL(register_pernet_device);
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/**
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* unregister_pernet_device - unregister a network namespace netdevice
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* @ops: pernet operations structure to manipulate
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*
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* Remove the pernet operations structure from the list to be
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* used when network namespaces are created or destoryed. In
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* addition run the exit method for all existing network
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* namespaces.
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*/
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void unregister_pernet_device(struct pernet_operations *ops)
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{
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mutex_lock(&net_mutex);
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if (&ops->list == first_device)
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first_device = first_device->next;
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unregister_pernet_operations(ops);
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mutex_unlock(&net_mutex);
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}
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EXPORT_SYMBOL_GPL(unregister_pernet_device);
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