linux-stable/net/core/fib_notifier.c
Jiri Pirko b7a595577e net: fib_notifier: propagate extack down to the notifier block callback
Since errors are propagated all the way up to the caller, propagate
possible extack of the caller all the way down to the notifier block
callback.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-10-04 11:10:56 -07:00

199 lines
4.8 KiB
C

#include <linux/rtnetlink.h>
#include <linux/notifier.h>
#include <linux/rcupdate.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <net/fib_notifier.h>
static unsigned int fib_notifier_net_id;
struct fib_notifier_net {
struct list_head fib_notifier_ops;
struct atomic_notifier_head fib_chain;
};
int call_fib_notifier(struct notifier_block *nb,
enum fib_event_type event_type,
struct fib_notifier_info *info)
{
int err;
err = nb->notifier_call(nb, event_type, info);
return notifier_to_errno(err);
}
EXPORT_SYMBOL(call_fib_notifier);
int call_fib_notifiers(struct net *net, enum fib_event_type event_type,
struct fib_notifier_info *info)
{
struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
int err;
err = atomic_notifier_call_chain(&fn_net->fib_chain, event_type, info);
return notifier_to_errno(err);
}
EXPORT_SYMBOL(call_fib_notifiers);
static unsigned int fib_seq_sum(struct net *net)
{
struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
struct fib_notifier_ops *ops;
unsigned int fib_seq = 0;
rtnl_lock();
rcu_read_lock();
list_for_each_entry_rcu(ops, &fn_net->fib_notifier_ops, list) {
if (!try_module_get(ops->owner))
continue;
fib_seq += ops->fib_seq_read(net);
module_put(ops->owner);
}
rcu_read_unlock();
rtnl_unlock();
return fib_seq;
}
static int fib_net_dump(struct net *net, struct notifier_block *nb,
struct netlink_ext_ack *extack)
{
struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
struct fib_notifier_ops *ops;
int err = 0;
rcu_read_lock();
list_for_each_entry_rcu(ops, &fn_net->fib_notifier_ops, list) {
if (!try_module_get(ops->owner))
continue;
err = ops->fib_dump(net, nb, extack);
module_put(ops->owner);
if (err)
goto unlock;
}
unlock:
rcu_read_unlock();
return err;
}
static bool fib_dump_is_consistent(struct net *net, struct notifier_block *nb,
void (*cb)(struct notifier_block *nb),
unsigned int fib_seq)
{
struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
atomic_notifier_chain_register(&fn_net->fib_chain, nb);
if (fib_seq == fib_seq_sum(net))
return true;
atomic_notifier_chain_unregister(&fn_net->fib_chain, nb);
if (cb)
cb(nb);
return false;
}
#define FIB_DUMP_MAX_RETRIES 5
int register_fib_notifier(struct net *net, struct notifier_block *nb,
void (*cb)(struct notifier_block *nb),
struct netlink_ext_ack *extack)
{
int retries = 0;
int err;
do {
unsigned int fib_seq = fib_seq_sum(net);
err = fib_net_dump(net, nb, extack);
if (err)
return err;
if (fib_dump_is_consistent(net, nb, cb, fib_seq))
return 0;
} while (++retries < FIB_DUMP_MAX_RETRIES);
return -EBUSY;
}
EXPORT_SYMBOL(register_fib_notifier);
int unregister_fib_notifier(struct net *net, struct notifier_block *nb)
{
struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
return atomic_notifier_chain_unregister(&fn_net->fib_chain, nb);
}
EXPORT_SYMBOL(unregister_fib_notifier);
static int __fib_notifier_ops_register(struct fib_notifier_ops *ops,
struct net *net)
{
struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
struct fib_notifier_ops *o;
list_for_each_entry(o, &fn_net->fib_notifier_ops, list)
if (ops->family == o->family)
return -EEXIST;
list_add_tail_rcu(&ops->list, &fn_net->fib_notifier_ops);
return 0;
}
struct fib_notifier_ops *
fib_notifier_ops_register(const struct fib_notifier_ops *tmpl, struct net *net)
{
struct fib_notifier_ops *ops;
int err;
ops = kmemdup(tmpl, sizeof(*ops), GFP_KERNEL);
if (!ops)
return ERR_PTR(-ENOMEM);
err = __fib_notifier_ops_register(ops, net);
if (err)
goto err_register;
return ops;
err_register:
kfree(ops);
return ERR_PTR(err);
}
EXPORT_SYMBOL(fib_notifier_ops_register);
void fib_notifier_ops_unregister(struct fib_notifier_ops *ops)
{
list_del_rcu(&ops->list);
kfree_rcu(ops, rcu);
}
EXPORT_SYMBOL(fib_notifier_ops_unregister);
static int __net_init fib_notifier_net_init(struct net *net)
{
struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
INIT_LIST_HEAD(&fn_net->fib_notifier_ops);
ATOMIC_INIT_NOTIFIER_HEAD(&fn_net->fib_chain);
return 0;
}
static void __net_exit fib_notifier_net_exit(struct net *net)
{
struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id);
WARN_ON_ONCE(!list_empty(&fn_net->fib_notifier_ops));
}
static struct pernet_operations fib_notifier_net_ops = {
.init = fib_notifier_net_init,
.exit = fib_notifier_net_exit,
.id = &fib_notifier_net_id,
.size = sizeof(struct fib_notifier_net),
};
static int __init fib_notifier_init(void)
{
return register_pernet_subsys(&fib_notifier_net_ops);
}
subsys_initcall(fib_notifier_init);