| #include <linux/workqueue.h> |
| #include <linux/rtnetlink.h> |
| #include <linux/cache.h> |
| #include <linux/slab.h> |
| #include <linux/list.h> |
| #include <linux/delay.h> |
| #include <linux/sched.h> |
| #include <linux/idr.h> |
| #include <linux/rculist.h> |
| #include <linux/nsproxy.h> |
| #include <net/net_namespace.h> |
| #include <net/netns/generic.h> |
| |
| /* |
| * Our network namespace constructor/destructor lists |
| */ |
| |
| static LIST_HEAD(pernet_list); |
| static struct list_head *first_device = &pernet_list; |
| static DEFINE_MUTEX(net_mutex); |
| |
| LIST_HEAD(net_namespace_list); |
| EXPORT_SYMBOL_GPL(net_namespace_list); |
| |
| 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. |
| */ |
| static __net_init int setup_net(struct net *net) |
| { |
| /* Must be called with net_mutex held */ |
| struct pernet_operations *ops; |
| int error = 0; |
| |
| atomic_set(&net->count, 1); |
| |
| #ifdef NETNS_REFCNT_DEBUG |
| atomic_set(&net->use_count, 0); |
| #endif |
| |
| list_for_each_entry(ops, &pernet_list, list) { |
| if (ops->init) { |
| error = ops->init(net); |
| if (error < 0) |
| goto out_undo; |
| } |
| } |
| out: |
| return error; |
| |
| out_undo: |
| /* Walk through the list backwards calling the exit functions |
| * for the pernet modules whose init functions did not fail. |
| */ |
| list_for_each_entry_continue_reverse(ops, &pernet_list, list) { |
| if (ops->exit) |
| ops->exit(net); |
| } |
| |
| rcu_barrier(); |
| goto out; |
| } |
| |
| static struct net_generic *net_alloc_generic(void) |
| { |
| struct net_generic *ng; |
| size_t generic_size = sizeof(struct net_generic) + |
| INITIAL_NET_GEN_PTRS * sizeof(void *); |
| |
| ng = kzalloc(generic_size, GFP_KERNEL); |
| if (ng) |
| ng->len = INITIAL_NET_GEN_PTRS; |
| |
| return ng; |
| } |
| |
| #ifdef CONFIG_NET_NS |
| static struct kmem_cache *net_cachep; |
| static struct workqueue_struct *netns_wq; |
| |
| static struct net *net_alloc(void) |
| { |
| struct net *net = NULL; |
| struct net_generic *ng; |
| |
| ng = net_alloc_generic(); |
| if (!ng) |
| goto out; |
| |
| net = kmem_cache_zalloc(net_cachep, GFP_KERNEL); |
| if (!net) |
| goto out_free; |
| |
| rcu_assign_pointer(net->gen, ng); |
| out: |
| return net; |
| |
| out_free: |
| kfree(ng); |
| goto out; |
| } |
| |
| static void net_free(struct net *net) |
| { |
| #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 |
| kfree(net->gen); |
| kmem_cache_free(net_cachep, net); |
| } |
| |
| static struct net *net_create(void) |
| { |
| struct net *net; |
| int rv; |
| |
| net = net_alloc(); |
| if (!net) |
| return ERR_PTR(-ENOMEM); |
| mutex_lock(&net_mutex); |
| rv = setup_net(net); |
| if (rv == 0) { |
| rtnl_lock(); |
| list_add_tail_rcu(&net->list, &net_namespace_list); |
| rtnl_unlock(); |
| } |
| mutex_unlock(&net_mutex); |
| if (rv < 0) { |
| net_free(net); |
| return ERR_PTR(rv); |
| } |
| return net; |
| } |
| |
| struct net *copy_net_ns(unsigned long flags, struct net *old_net) |
| { |
| if (!(flags & CLONE_NEWNET)) |
| return get_net(old_net); |
| return net_create(); |
| } |
| |
| static void cleanup_net(struct work_struct *work) |
| { |
| struct pernet_operations *ops; |
| struct net *net; |
| |
| net = container_of(work, struct net, work); |
| |
| mutex_lock(&net_mutex); |
| |
| /* Don't let anyone else find us. */ |
| rtnl_lock(); |
| list_del_rcu(&net->list); |
| rtnl_unlock(); |
| |
| /* |
| * Another CPU might be rcu-iterating the list, wait for it. |
| * This needs to be before calling the exit() notifiers, so |
| * the rcu_barrier() below isn't sufficient alone. |
| */ |
| synchronize_rcu(); |
| |
| /* Run all of the network namespace exit methods */ |
| list_for_each_entry_reverse(ops, &pernet_list, list) { |
| if (ops->exit) |
| ops->exit(net); |
| } |
| |
| mutex_unlock(&net_mutex); |
| |
| /* Ensure there are no outstanding rcu callbacks using this |
| * network namespace. |
| */ |
| rcu_barrier(); |
| |
| /* Finally it is safe to free my network namespace structure */ |
| net_free(net); |
| } |
| |
| void __put_net(struct net *net) |
| { |
| /* Cleanup the network namespace in process context */ |
| INIT_WORK(&net->work, cleanup_net); |
| queue_work(netns_wq, &net->work); |
| } |
| EXPORT_SYMBOL_GPL(__put_net); |
| |
| #else |
| struct net *copy_net_ns(unsigned long flags, struct net *old_net) |
| { |
| if (flags & CLONE_NEWNET) |
| return ERR_PTR(-EINVAL); |
| return old_net; |
| } |
| #endif |
| |
| struct net *get_net_ns_by_pid(pid_t pid) |
| { |
| struct task_struct *tsk; |
| struct net *net; |
| |
| /* Lookup the network namespace */ |
| net = ERR_PTR(-ESRCH); |
| rcu_read_lock(); |
| tsk = find_task_by_vpid(pid); |
| if (tsk) { |
| struct nsproxy *nsproxy; |
| nsproxy = task_nsproxy(tsk); |
| if (nsproxy) |
| net = get_net(nsproxy->net_ns); |
| } |
| rcu_read_unlock(); |
| return net; |
| } |
| EXPORT_SYMBOL_GPL(get_net_ns_by_pid); |
| |
| static int __init net_ns_init(void) |
| { |
| struct net_generic *ng; |
| |
| #ifdef CONFIG_NET_NS |
| net_cachep = kmem_cache_create("net_namespace", sizeof(struct net), |
| SMP_CACHE_BYTES, |
| SLAB_PANIC, NULL); |
| |
| /* Create workqueue for cleanup */ |
| netns_wq = create_singlethread_workqueue("netns"); |
| if (!netns_wq) |
| panic("Could not create netns workq"); |
| #endif |
| |
| ng = net_alloc_generic(); |
| if (!ng) |
| panic("Could not allocate generic netns"); |
| |
| rcu_assign_pointer(init_net.gen, ng); |
| |
| mutex_lock(&net_mutex); |
| if (setup_net(&init_net)) |
| panic("Could not setup the initial network namespace"); |
| |
| rtnl_lock(); |
| list_add_tail_rcu(&init_net.list, &net_namespace_list); |
| rtnl_unlock(); |
| |
| mutex_unlock(&net_mutex); |
| |
| return 0; |
| } |
| |
| pure_initcall(net_ns_init); |
| |
| #ifdef CONFIG_NET_NS |
| static int register_pernet_operations(struct list_head *list, |
| struct pernet_operations *ops) |
| { |
| struct net *net, *undo_net; |
| int error; |
| |
| list_add_tail(&ops->list, list); |
| if (ops->init) { |
| for_each_net(net) { |
| error = ops->init(net); |
| if (error) |
| goto out_undo; |
| } |
| } |
| return 0; |
| |
| out_undo: |
| /* If I have an error cleanup all namespaces I initialized */ |
| list_del(&ops->list); |
| if (ops->exit) { |
| for_each_net(undo_net) { |
| if (undo_net == net) |
| goto undone; |
| ops->exit(undo_net); |
| } |
| } |
| undone: |
| return error; |
| } |
| |
| static void unregister_pernet_operations(struct pernet_operations *ops) |
| { |
| struct net *net; |
| |
| list_del(&ops->list); |
| if (ops->exit) |
| for_each_net(net) |
| ops->exit(net); |
| } |
| |
| #else |
| |
| static int register_pernet_operations(struct list_head *list, |
| struct pernet_operations *ops) |
| { |
| if (ops->init == NULL) |
| return 0; |
| return ops->init(&init_net); |
| } |
| |
| static void unregister_pernet_operations(struct pernet_operations *ops) |
| { |
| if (ops->exit) |
| ops->exit(&init_net); |
| } |
| #endif |
| |
| static DEFINE_IDA(net_generic_ids); |
| |
| /** |
| * register_pernet_subsys - register a network namespace subsystem |
| * @ops: pernet operations structure for the subsystem |
| * |
| * Register a subsystem which has init and exit functions |
| * that are called when network namespaces are created and |
| * destroyed respectively. |
| * |
| * When registered all network namespace init functions are |
| * called for every existing network namespace. Allowing kernel |
| * modules to have a race free view of the set of network namespaces. |
| * |
| * When a new network namespace is created all of the init |
| * methods are called in the order in which they were registered. |
| * |
| * When a network namespace is destroyed all of the exit methods |
| * are called in the reverse of the order with which they were |
| * registered. |
| */ |
| int register_pernet_subsys(struct pernet_operations *ops) |
| { |
| int error; |
| mutex_lock(&net_mutex); |
| error = register_pernet_operations(first_device, ops); |
| mutex_unlock(&net_mutex); |
| return error; |
| } |
| EXPORT_SYMBOL_GPL(register_pernet_subsys); |
| |
| /** |
| * unregister_pernet_subsys - unregister a network namespace subsystem |
| * @ops: pernet operations structure to manipulate |
| * |
| * Remove the pernet operations structure from the list to be |
| * used when network namespaces are created or destroyed. In |
| * addition run the exit method for all existing network |
| * namespaces. |
| */ |
| void unregister_pernet_subsys(struct pernet_operations *module) |
| { |
| mutex_lock(&net_mutex); |
| unregister_pernet_operations(module); |
| mutex_unlock(&net_mutex); |
| } |
| EXPORT_SYMBOL_GPL(unregister_pernet_subsys); |
| |
| int register_pernet_gen_subsys(int *id, struct pernet_operations *ops) |
| { |
| int rv; |
| |
| mutex_lock(&net_mutex); |
| again: |
| rv = ida_get_new_above(&net_generic_ids, 1, id); |
| if (rv < 0) { |
| if (rv == -EAGAIN) { |
| ida_pre_get(&net_generic_ids, GFP_KERNEL); |
| goto again; |
| } |
| goto out; |
| } |
| rv = register_pernet_operations(first_device, ops); |
| if (rv < 0) |
| ida_remove(&net_generic_ids, *id); |
| out: |
| mutex_unlock(&net_mutex); |
| return rv; |
| } |
| EXPORT_SYMBOL_GPL(register_pernet_gen_subsys); |
| |
| void unregister_pernet_gen_subsys(int id, struct pernet_operations *ops) |
| { |
| mutex_lock(&net_mutex); |
| unregister_pernet_operations(ops); |
| ida_remove(&net_generic_ids, id); |
| mutex_unlock(&net_mutex); |
| } |
| EXPORT_SYMBOL_GPL(unregister_pernet_gen_subsys); |
| |
| /** |
| * register_pernet_device - register a network namespace device |
| * @ops: pernet operations structure for the subsystem |
| * |
| * Register a device which has init and exit functions |
| * that are called when network namespaces are created and |
| * destroyed respectively. |
| * |
| * When registered all network namespace init functions are |
| * called for every existing network namespace. Allowing kernel |
| * modules to have a race free view of the set of network namespaces. |
| * |
| * When a new network namespace is created all of the init |
| * methods are called in the order in which they were registered. |
| * |
| * When a network namespace is destroyed all of the exit methods |
| * are called in the reverse of the order with which they were |
| * registered. |
| */ |
| int register_pernet_device(struct pernet_operations *ops) |
| { |
| int error; |
| mutex_lock(&net_mutex); |
| error = register_pernet_operations(&pernet_list, ops); |
| if (!error && (first_device == &pernet_list)) |
| first_device = &ops->list; |
| mutex_unlock(&net_mutex); |
| return error; |
| } |
| EXPORT_SYMBOL_GPL(register_pernet_device); |
| |
| int register_pernet_gen_device(int *id, struct pernet_operations *ops) |
| { |
| int error; |
| mutex_lock(&net_mutex); |
| again: |
| error = ida_get_new_above(&net_generic_ids, 1, id); |
| if (error) { |
| if (error == -EAGAIN) { |
| ida_pre_get(&net_generic_ids, GFP_KERNEL); |
| goto again; |
| } |
| goto out; |
| } |
| error = register_pernet_operations(&pernet_list, ops); |
| if (error) |
| ida_remove(&net_generic_ids, *id); |
| else if (first_device == &pernet_list) |
| first_device = &ops->list; |
| out: |
| mutex_unlock(&net_mutex); |
| return error; |
| } |
| EXPORT_SYMBOL_GPL(register_pernet_gen_device); |
| |
| /** |
| * unregister_pernet_device - unregister a network namespace netdevice |
| * @ops: pernet operations structure to manipulate |
| * |
| * Remove the pernet operations structure from the list to be |
| * used when network namespaces are created or destroyed. In |
| * addition run the exit method for all existing network |
| * namespaces. |
| */ |
| void unregister_pernet_device(struct pernet_operations *ops) |
| { |
| mutex_lock(&net_mutex); |
| if (&ops->list == first_device) |
| first_device = first_device->next; |
| unregister_pernet_operations(ops); |
| mutex_unlock(&net_mutex); |
| } |
| EXPORT_SYMBOL_GPL(unregister_pernet_device); |
| |
| void unregister_pernet_gen_device(int id, struct pernet_operations *ops) |
| { |
| mutex_lock(&net_mutex); |
| if (&ops->list == first_device) |
| first_device = first_device->next; |
| unregister_pernet_operations(ops); |
| ida_remove(&net_generic_ids, id); |
| 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; |
| 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); |