636 lines
14 KiB
C
636 lines
14 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 <linux/sched.h>
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#include <linux/idr.h>
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#include <linux/rculist.h>
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#include <linux/nsproxy.h>
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#include <linux/proc_fs.h>
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#include <linux/file.h>
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#include <net/net_namespace.h>
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#include <net/netns/generic.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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LIST_HEAD(net_namespace_list);
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EXPORT_SYMBOL_GPL(net_namespace_list);
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struct net init_net;
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EXPORT_SYMBOL(init_net);
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#define INITIAL_NET_GEN_PTRS 13 /* +1 for len +2 for rcu_head */
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static int net_assign_generic(struct net *net, int id, void *data)
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{
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struct net_generic *ng, *old_ng;
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BUG_ON(!mutex_is_locked(&net_mutex));
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BUG_ON(id == 0);
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old_ng = rcu_dereference_protected(net->gen,
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lockdep_is_held(&net_mutex));
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ng = old_ng;
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if (old_ng->len >= id)
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goto assign;
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ng = kzalloc(sizeof(struct net_generic) +
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id * sizeof(void *), GFP_KERNEL);
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if (ng == NULL)
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return -ENOMEM;
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/*
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* Some synchronisation notes:
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*
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* The net_generic explores the net->gen array inside rcu
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* read section. Besides once set the net->gen->ptr[x]
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* pointer never changes (see rules in netns/generic.h).
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*
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* That said, we simply duplicate this array and schedule
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* the old copy for kfree after a grace period.
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*/
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ng->len = id;
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memcpy(&ng->ptr, &old_ng->ptr, old_ng->len * sizeof(void*));
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rcu_assign_pointer(net->gen, ng);
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kfree_rcu(old_ng, rcu);
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assign:
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ng->ptr[id - 1] = data;
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return 0;
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}
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static int ops_init(const struct pernet_operations *ops, struct net *net)
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{
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int err;
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if (ops->id && ops->size) {
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void *data = kzalloc(ops->size, GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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err = net_assign_generic(net, *ops->id, data);
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if (err) {
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kfree(data);
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return err;
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}
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}
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if (ops->init)
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return ops->init(net);
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return 0;
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}
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static void ops_free(const struct pernet_operations *ops, struct net *net)
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{
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if (ops->id && ops->size) {
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int id = *ops->id;
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kfree(net_generic(net, id));
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}
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}
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static void ops_exit_list(const struct pernet_operations *ops,
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struct list_head *net_exit_list)
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{
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struct net *net;
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if (ops->exit) {
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list_for_each_entry(net, net_exit_list, exit_list)
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ops->exit(net);
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}
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if (ops->exit_batch)
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ops->exit_batch(net_exit_list);
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}
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static void ops_free_list(const struct pernet_operations *ops,
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struct list_head *net_exit_list)
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{
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struct net *net;
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if (ops->size && ops->id) {
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list_for_each_entry(net, net_exit_list, exit_list)
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ops_free(ops, net);
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}
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}
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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 __net_init 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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const struct pernet_operations *ops, *saved_ops;
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int error = 0;
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LIST_HEAD(net_exit_list);
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atomic_set(&net->count, 1);
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atomic_set(&net->passive, 1);
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net->dev_base_seq = 1;
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#ifdef NETNS_REFCNT_DEBUG
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atomic_set(&net->use_count, 0);
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#endif
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list_for_each_entry(ops, &pernet_list, list) {
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error = ops_init(ops, net);
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if (error < 0)
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goto out_undo;
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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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list_add(&net->exit_list, &net_exit_list);
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saved_ops = ops;
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list_for_each_entry_continue_reverse(ops, &pernet_list, list)
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ops_exit_list(ops, &net_exit_list);
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ops = saved_ops;
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list_for_each_entry_continue_reverse(ops, &pernet_list, list)
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ops_free_list(ops, &net_exit_list);
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rcu_barrier();
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goto out;
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}
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static struct net_generic *net_alloc_generic(void)
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{
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struct net_generic *ng;
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size_t generic_size = sizeof(struct net_generic) +
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INITIAL_NET_GEN_PTRS * sizeof(void *);
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ng = kzalloc(generic_size, GFP_KERNEL);
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if (ng)
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ng->len = INITIAL_NET_GEN_PTRS;
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return ng;
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}
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#ifdef CONFIG_NET_NS
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static struct kmem_cache *net_cachep;
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static struct workqueue_struct *netns_wq;
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static struct net *net_alloc(void)
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{
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struct net *net = NULL;
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struct net_generic *ng;
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ng = net_alloc_generic();
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if (!ng)
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goto out;
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net = kmem_cache_zalloc(net_cachep, GFP_KERNEL);
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if (!net)
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goto out_free;
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rcu_assign_pointer(net->gen, ng);
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out:
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return net;
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out_free:
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kfree(ng);
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goto out;
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}
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static void net_free(struct net *net)
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{
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#ifdef NETNS_REFCNT_DEBUG
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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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#endif
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kfree(net->gen);
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kmem_cache_free(net_cachep, net);
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}
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void net_drop_ns(void *p)
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{
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struct net *ns = p;
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if (ns && atomic_dec_and_test(&ns->passive))
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net_free(ns);
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}
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struct net *copy_net_ns(unsigned long flags, struct net *old_net)
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{
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struct net *net;
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int rv;
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if (!(flags & CLONE_NEWNET))
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return get_net(old_net);
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net = net_alloc();
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if (!net)
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return ERR_PTR(-ENOMEM);
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mutex_lock(&net_mutex);
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rv = setup_net(net);
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if (rv == 0) {
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rtnl_lock();
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list_add_tail_rcu(&net->list, &net_namespace_list);
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rtnl_unlock();
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}
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mutex_unlock(&net_mutex);
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if (rv < 0) {
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net_drop_ns(net);
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return ERR_PTR(rv);
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}
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return net;
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}
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static DEFINE_SPINLOCK(cleanup_list_lock);
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static LIST_HEAD(cleanup_list); /* Must hold cleanup_list_lock to touch */
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static void cleanup_net(struct work_struct *work)
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{
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const struct pernet_operations *ops;
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struct net *net, *tmp;
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LIST_HEAD(net_kill_list);
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LIST_HEAD(net_exit_list);
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/* Atomically snapshot the list of namespaces to cleanup */
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spin_lock_irq(&cleanup_list_lock);
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list_replace_init(&cleanup_list, &net_kill_list);
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spin_unlock_irq(&cleanup_list_lock);
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mutex_lock(&net_mutex);
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/* Don't let anyone else find us. */
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rtnl_lock();
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list_for_each_entry(net, &net_kill_list, cleanup_list) {
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list_del_rcu(&net->list);
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list_add_tail(&net->exit_list, &net_exit_list);
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}
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rtnl_unlock();
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/*
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* Another CPU might be rcu-iterating the list, wait for it.
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* This needs to be before calling the exit() notifiers, so
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* the rcu_barrier() below isn't sufficient alone.
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*/
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synchronize_rcu();
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/* Run all of the network namespace exit methods */
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list_for_each_entry_reverse(ops, &pernet_list, list)
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ops_exit_list(ops, &net_exit_list);
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/* Free the net generic variables */
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list_for_each_entry_reverse(ops, &pernet_list, list)
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ops_free_list(ops, &net_exit_list);
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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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list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) {
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list_del_init(&net->exit_list);
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net_drop_ns(net);
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}
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}
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static DECLARE_WORK(net_cleanup_work, cleanup_net);
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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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unsigned long flags;
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spin_lock_irqsave(&cleanup_list_lock, flags);
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list_add(&net->cleanup_list, &cleanup_list);
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spin_unlock_irqrestore(&cleanup_list_lock, flags);
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queue_work(netns_wq, &net_cleanup_work);
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}
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EXPORT_SYMBOL_GPL(__put_net);
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struct net *get_net_ns_by_fd(int fd)
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{
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struct proc_inode *ei;
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struct file *file;
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struct net *net;
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file = proc_ns_fget(fd);
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if (IS_ERR(file))
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return ERR_CAST(file);
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ei = PROC_I(file->f_dentry->d_inode);
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if (ei->ns_ops == &netns_operations)
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net = get_net(ei->ns);
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else
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net = ERR_PTR(-EINVAL);
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fput(file);
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return net;
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}
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#else
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struct net *copy_net_ns(unsigned long flags, struct net *old_net)
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{
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if (flags & CLONE_NEWNET)
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return ERR_PTR(-EINVAL);
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return old_net;
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}
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struct net *get_net_ns_by_fd(int fd)
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{
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return ERR_PTR(-EINVAL);
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}
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#endif
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struct net *get_net_ns_by_pid(pid_t pid)
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{
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struct task_struct *tsk;
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struct net *net;
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/* Lookup the network namespace */
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net = ERR_PTR(-ESRCH);
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rcu_read_lock();
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tsk = find_task_by_vpid(pid);
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if (tsk) {
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struct nsproxy *nsproxy;
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nsproxy = task_nsproxy(tsk);
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if (nsproxy)
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net = get_net(nsproxy->net_ns);
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}
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rcu_read_unlock();
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return net;
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}
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EXPORT_SYMBOL_GPL(get_net_ns_by_pid);
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static int __init net_ns_init(void)
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{
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struct net_generic *ng;
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#ifdef CONFIG_NET_NS
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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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/* Create workqueue for cleanup */
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netns_wq = create_singlethread_workqueue("netns");
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if (!netns_wq)
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panic("Could not create netns workq");
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#endif
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ng = net_alloc_generic();
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if (!ng)
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panic("Could not allocate generic netns");
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rcu_assign_pointer(init_net.gen, ng);
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mutex_lock(&net_mutex);
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if (setup_net(&init_net))
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panic("Could not setup the initial network namespace");
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rtnl_lock();
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list_add_tail_rcu(&init_net.list, &net_namespace_list);
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rtnl_unlock();
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mutex_unlock(&net_mutex);
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return 0;
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}
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pure_initcall(net_ns_init);
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#ifdef CONFIG_NET_NS
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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;
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int error;
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LIST_HEAD(net_exit_list);
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list_add_tail(&ops->list, list);
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if (ops->init || (ops->id && ops->size)) {
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for_each_net(net) {
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error = ops_init(ops, net);
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if (error)
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goto out_undo;
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list_add_tail(&net->exit_list, &net_exit_list);
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}
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}
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return 0;
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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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ops_exit_list(ops, &net_exit_list);
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ops_free_list(ops, &net_exit_list);
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return error;
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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_HEAD(net_exit_list);
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list_del(&ops->list);
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for_each_net(net)
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list_add_tail(&net->exit_list, &net_exit_list);
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ops_exit_list(ops, &net_exit_list);
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ops_free_list(ops, &net_exit_list);
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}
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#else
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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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int err = 0;
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err = ops_init(ops, &init_net);
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if (err)
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ops_free(ops, &init_net);
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return err;
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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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LIST_HEAD(net_exit_list);
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list_add(&init_net.exit_list, &net_exit_list);
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ops_exit_list(ops, &net_exit_list);
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ops_free_list(ops, &net_exit_list);
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}
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#endif /* CONFIG_NET_NS */
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static DEFINE_IDA(net_generic_ids);
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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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int error;
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if (ops->id) {
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again:
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error = ida_get_new_above(&net_generic_ids, 1, ops->id);
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if (error < 0) {
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if (error == -EAGAIN) {
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ida_pre_get(&net_generic_ids, GFP_KERNEL);
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goto again;
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}
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return error;
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}
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}
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error = __register_pernet_operations(list, ops);
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if (error) {
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rcu_barrier();
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if (ops->id)
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ida_remove(&net_generic_ids, *ops->id);
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}
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return error;
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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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__unregister_pernet_operations(ops);
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rcu_barrier();
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if (ops->id)
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ida_remove(&net_generic_ids, *ops->id);
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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 destroyed. 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 *ops)
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{
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mutex_lock(&net_mutex);
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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_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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*
|
|
* 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);
|
|
|
|
/**
|
|
* 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);
|
|
|
|
#ifdef CONFIG_NET_NS
|
|
static void *netns_get(struct task_struct *task)
|
|
{
|
|
struct net *net = NULL;
|
|
struct nsproxy *nsproxy;
|
|
|
|
rcu_read_lock();
|
|
nsproxy = task_nsproxy(task);
|
|
if (nsproxy)
|
|
net = get_net(nsproxy->net_ns);
|
|
rcu_read_unlock();
|
|
|
|
return net;
|
|
}
|
|
|
|
static void netns_put(void *ns)
|
|
{
|
|
put_net(ns);
|
|
}
|
|
|
|
static int netns_install(struct nsproxy *nsproxy, void *ns)
|
|
{
|
|
put_net(nsproxy->net_ns);
|
|
nsproxy->net_ns = get_net(ns);
|
|
return 0;
|
|
}
|
|
|
|
const struct proc_ns_operations netns_operations = {
|
|
.name = "net",
|
|
.type = CLONE_NEWNET,
|
|
.get = netns_get,
|
|
.put = netns_put,
|
|
.install = netns_install,
|
|
};
|
|
#endif
|