diff options
Diffstat (limited to 'net/core/fib_notifier.c')
| -rw-r--r-- | net/core/fib_notifier.c | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/net/core/fib_notifier.c b/net/core/fib_notifier.c new file mode 100644 index 000000000..fc9625980 --- /dev/null +++ b/net/core/fib_notifier.c @@ -0,0 +1,199 @@ +#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); |