|  | #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 <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); | 
|  |  | 
|  | 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; | 
|  | 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) { | 
|  | 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(); | 
|  | kfree(ng); | 
|  | goto out; | 
|  | } | 
|  |  | 
|  | #ifdef CONFIG_NET_NS | 
|  | static struct kmem_cache *net_cachep; | 
|  | static struct workqueue_struct *netns_wq; | 
|  |  | 
|  | static struct net *net_alloc(void) | 
|  | { | 
|  | return kmem_cache_zalloc(net_cachep, GFP_KERNEL); | 
|  | } | 
|  |  | 
|  | static void net_free(struct net *net) | 
|  | { | 
|  | 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 net *copy_net_ns(unsigned long flags, struct net *old_net) | 
|  | { | 
|  | struct net *new_net = NULL; | 
|  | int err; | 
|  |  | 
|  | get_net(old_net); | 
|  |  | 
|  | if (!(flags & CLONE_NEWNET)) | 
|  | return old_net; | 
|  |  | 
|  | err = -ENOMEM; | 
|  | new_net = net_alloc(); | 
|  | if (!new_net) | 
|  | goto out; | 
|  |  | 
|  | mutex_lock(&net_mutex); | 
|  | err = setup_net(new_net); | 
|  | if (err) | 
|  | goto out_unlock; | 
|  |  | 
|  | rtnl_lock(); | 
|  | list_add_tail(&new_net->list, &net_namespace_list); | 
|  | rtnl_unlock(); | 
|  |  | 
|  |  | 
|  | out_unlock: | 
|  | mutex_unlock(&net_mutex); | 
|  | out: | 
|  | put_net(old_net); | 
|  | if (err) { | 
|  | net_free(new_net); | 
|  | new_net = ERR_PTR(err); | 
|  | } | 
|  | return new_net; | 
|  | } | 
|  |  | 
|  | 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(&net->list); | 
|  | rtnl_unlock(); | 
|  |  | 
|  | /* 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 | 
|  |  | 
|  | static int __init net_ns_init(void) | 
|  | { | 
|  | int err; | 
|  |  | 
|  | printk(KERN_INFO "net_namespace: %zd bytes\n", sizeof(struct net)); | 
|  | #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 | 
|  |  | 
|  | mutex_lock(&net_mutex); | 
|  | err = setup_net(&init_net); | 
|  |  | 
|  | rtnl_lock(); | 
|  | list_add_tail(&init_net.list, &net_namespace_list); | 
|  | rtnl_unlock(); | 
|  |  | 
|  | mutex_unlock(&net_mutex); | 
|  | if (err) | 
|  | panic("Could not setup the initial network namespace"); | 
|  |  | 
|  | 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); | 
|  |  | 
|  | /** | 
|  | *      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; | 
|  | 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); |