diff options
| -rw-r--r-- | net/netfilter/core.c | 108 |
1 files changed, 33 insertions, 75 deletions
diff --git a/net/netfilter/core.c b/net/netfilter/core.c index c9d90eb..fcb5d1d 100644 --- a/net/netfilter/core.c +++ b/net/netfilter/core.c @@ -65,49 +65,24 @@ static DEFINE_MUTEX(nf_hook_mutex); #define nf_entry_dereference(e) \ rcu_dereference_protected(e, lockdep_is_held(&nf_hook_mutex)) -static struct nf_hook_entry *nf_hook_entry_head(struct net *net, - const struct nf_hook_ops *reg) +static struct nf_hook_entry __rcu **nf_hook_entry_head(struct net *net, const struct nf_hook_ops *reg) { - struct nf_hook_entry *hook_head = NULL; - if (reg->pf != NFPROTO_NETDEV) - hook_head = nf_entry_dereference(net->nf.hooks[reg->pf] - [reg->hooknum]); - else if (reg->hooknum == NF_NETDEV_INGRESS) { + return net->nf.hooks[reg->pf]+reg->hooknum; + #ifdef CONFIG_NETFILTER_INGRESS + if (reg->hooknum == NF_NETDEV_INGRESS) { if (reg->dev && dev_net(reg->dev) == net) - hook_head = - nf_entry_dereference( - reg->dev->nf_hooks_ingress); -#endif + return ®->dev->nf_hooks_ingress; } - return hook_head; -} - -/* must hold nf_hook_mutex */ -static void nf_set_hooks_head(struct net *net, const struct nf_hook_ops *reg, - struct nf_hook_entry *entry) -{ - switch (reg->pf) { - case NFPROTO_NETDEV: -#ifdef CONFIG_NETFILTER_INGRESS - /* We already checked in nf_register_net_hook() that this is - * used from ingress. - */ - rcu_assign_pointer(reg->dev->nf_hooks_ingress, entry); #endif - break; - default: - rcu_assign_pointer(net->nf.hooks[reg->pf][reg->hooknum], - entry); - break; - } + return NULL; } int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg) { - struct nf_hook_entry *hooks_entry; - struct nf_hook_entry *entry; + struct nf_hook_entry __rcu **pp; + struct nf_hook_entry *entry, *p; if (reg->pf == NFPROTO_NETDEV) { #ifndef CONFIG_NETFILTER_INGRESS @@ -119,6 +94,10 @@ int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg) return -EINVAL; } + pp = nf_hook_entry_head(net, reg); + if (!pp) + return -EINVAL; + entry = kmalloc(sizeof(*entry), GFP_KERNEL); if (!entry) return -ENOMEM; @@ -128,26 +107,15 @@ int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg) entry->next = NULL; mutex_lock(&nf_hook_mutex); - hooks_entry = nf_hook_entry_head(net, reg); - - if (hooks_entry && hooks_entry->orig_ops->priority > reg->priority) { - /* This is the case where we need to insert at the head */ - entry->next = hooks_entry; - hooks_entry = NULL; - } - - while (hooks_entry && - reg->priority >= hooks_entry->orig_ops->priority && - nf_entry_dereference(hooks_entry->next)) { - hooks_entry = nf_entry_dereference(hooks_entry->next); - } - if (hooks_entry) { - entry->next = nf_entry_dereference(hooks_entry->next); - rcu_assign_pointer(hooks_entry->next, entry); - } else { - nf_set_hooks_head(net, reg, entry); + /* Find the spot in the list */ + while ((p = nf_entry_dereference(*pp)) != NULL) { + if (reg->priority < p->orig_ops->priority) + break; + pp = &p->next; } + rcu_assign_pointer(entry->next, p); + rcu_assign_pointer(*pp, entry); mutex_unlock(&nf_hook_mutex); #ifdef CONFIG_NETFILTER_INGRESS @@ -163,33 +131,23 @@ EXPORT_SYMBOL(nf_register_net_hook); void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *reg) { - struct nf_hook_entry *hooks_entry; + struct nf_hook_entry __rcu **pp; + struct nf_hook_entry *p; - mutex_lock(&nf_hook_mutex); - hooks_entry = nf_hook_entry_head(net, reg); - if (hooks_entry && hooks_entry->orig_ops == reg) { - nf_set_hooks_head(net, reg, - nf_entry_dereference(hooks_entry->next)); - goto unlock; - } - while (hooks_entry && nf_entry_dereference(hooks_entry->next)) { - struct nf_hook_entry *next = - nf_entry_dereference(hooks_entry->next); - struct nf_hook_entry *nnext; + pp = nf_hook_entry_head(net, reg); + if (WARN_ON_ONCE(!pp)) + return; - if (next->orig_ops != reg) { - hooks_entry = next; - continue; + mutex_lock(&nf_hook_mutex); + while ((p = nf_entry_dereference(*pp)) != NULL) { + if (p->orig_ops == reg) { + rcu_assign_pointer(*pp, p->next); + break; } - nnext = nf_entry_dereference(next->next); - rcu_assign_pointer(hooks_entry->next, nnext); - hooks_entry = next; - break; + pp = &p->next; } - -unlock: mutex_unlock(&nf_hook_mutex); - if (!hooks_entry) { + if (!p) { WARN(1, "nf_unregister_net_hook: hook not found!\n"); return; } @@ -201,10 +159,10 @@ unlock: static_key_slow_dec(&nf_hooks_needed[reg->pf][reg->hooknum]); #endif synchronize_net(); - nf_queue_nf_hook_drop(net, hooks_entry); + nf_queue_nf_hook_drop(net, p); /* other cpu might still process nfqueue verdict that used reg */ synchronize_net(); - kfree(hooks_entry); + kfree(p); } EXPORT_SYMBOL(nf_unregister_net_hook); |