491 lines
11 KiB
C
491 lines
11 KiB
C
#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);
|
|
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;
|
|
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
|
|
kfree(net->gen);
|
|
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;
|
|
|
|
/* Be very certain incoming network packets will not find us */
|
|
rcu_barrier();
|
|
|
|
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);
|
|
|
|
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);
|
|
mutex_unlock(&net_mutex);
|
|
out:
|
|
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;
|
|
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);
|