From: Florian Westphal <fw@xxxxxxxxx>
This will allow the nat core to reuse the nf_hook infrastructure
to maintain nat lookup functions.
The raw versions don't assume a particular hook location, the
functions get added/deleted from the hook blob that is passed to the
functions.
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
net/netfilter/core.c | 75 +++++++++++++++++++++++++++++++-------------
net/netfilter/nf_internals.h | 5 +++
2 files changed, 59 insertions(+), 21 deletions(-)
diff --git a/net/netfilter/core.c b/net/netfilter/core.c
index 0f6b8172fb9a..5f0ebf9a8d5b 100644
--- a/net/netfilter/core.c
+++ b/net/netfilter/core.c
@@ -186,9 +186,31 @@ static void hooks_validate(const struct nf_hook_entries *hooks)
#endif
}
+int nf_hook_entries_insert_raw(struct nf_hook_entries __rcu **pp,
+ const struct nf_hook_ops *reg)
+{
+ struct nf_hook_entries *new_hooks;
+ struct nf_hook_entries *p;
+
+ p = rcu_dereference_raw(*pp);
+ new_hooks = nf_hook_entries_grow(p, reg);
+ if (IS_ERR(new_hooks))
+ return PTR_ERR(new_hooks);
+
+ hooks_validate(new_hooks);
+
+ rcu_assign_pointer(*pp, new_hooks);
+
+ BUG_ON(p == new_hooks);
+ nf_hook_entries_free(p);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(nf_hook_entries_insert_raw);
+
/*
* __nf_hook_entries_try_shrink - try to shrink hook array
*
+ * @old -- current hook blob at @pp
* @pp -- location of hook blob
*
* Hook unregistration must always succeed, so to-be-removed hooks
@@ -201,14 +223,14 @@ static void hooks_validate(const struct nf_hook_entries *hooks)
*
* Returns address to free, or NULL.
*/
-static void *__nf_hook_entries_try_shrink(struct nf_hook_entries __rcu **pp)
+static void *__nf_hook_entries_try_shrink(struct nf_hook_entries *old,
+ struct nf_hook_entries __rcu **pp)
{
- struct nf_hook_entries *old, *new = NULL;
unsigned int i, j, skip = 0, hook_entries;
+ struct nf_hook_entries *new = NULL;
struct nf_hook_ops **orig_ops;
struct nf_hook_ops **new_ops;
- old = nf_entry_dereference(*pp);
if (WARN_ON_ONCE(!old))
return NULL;
@@ -347,11 +369,10 @@ static int __nf_register_net_hook(struct net *net, int pf,
* This cannot fail, hook unregistration must always succeed.
* Therefore replace the to-be-removed hook with a dummy hook.
*/
-static void nf_remove_net_hook(struct nf_hook_entries *old,
- const struct nf_hook_ops *unreg, int pf)
+static bool nf_remove_net_hook(struct nf_hook_entries *old,
+ const struct nf_hook_ops *unreg)
{
struct nf_hook_ops **orig_ops;
- bool found = false;
unsigned int i;
orig_ops = nf_hook_entries_get_hook_ops(old);
@@ -360,21 +381,10 @@ static void nf_remove_net_hook(struct nf_hook_entries *old,
continue;
WRITE_ONCE(old->hooks[i].hook, accept_all);
WRITE_ONCE(orig_ops[i], &dummy_ops);
- found = true;
- break;
+ return true;
}
- if (found) {
-#ifdef CONFIG_NETFILTER_INGRESS
- if (pf == NFPROTO_NETDEV && unreg->hooknum == NF_NETDEV_INGRESS)
- net_dec_ingress_queue();
-#endif
-#ifdef HAVE_JUMP_LABEL
- static_key_slow_dec(&nf_hooks_needed[pf][unreg->hooknum]);
-#endif
- } else {
- WARN_ONCE(1, "hook not found, pf %d num %d", pf, unreg->hooknum);
- }
+ return false;
}
static void __nf_unregister_net_hook(struct net *net, int pf,
@@ -395,9 +405,19 @@ static void __nf_unregister_net_hook(struct net *net, int pf,
return;
}
- nf_remove_net_hook(p, reg, pf);
+ if (nf_remove_net_hook(p, reg)) {
+#ifdef CONFIG_NETFILTER_INGRESS
+ if (pf == NFPROTO_NETDEV && reg->hooknum == NF_NETDEV_INGRESS)
+ net_dec_ingress_queue();
+#endif
+#ifdef HAVE_JUMP_LABEL
+ static_key_slow_dec(&nf_hooks_needed[pf][reg->hooknum]);
+#endif
+ } else {
+ WARN_ONCE(1, "hook not found, pf %d num %d", pf, reg->hooknum);
+ }
- p = __nf_hook_entries_try_shrink(pp);
+ p = __nf_hook_entries_try_shrink(p, pp);
mutex_unlock(&nf_hook_mutex);
if (!p)
return;
@@ -417,6 +437,19 @@ void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *reg)
}
EXPORT_SYMBOL(nf_unregister_net_hook);
+void nf_hook_entries_delete_raw(struct nf_hook_entries __rcu **pp,
+ const struct nf_hook_ops *reg)
+{
+ struct nf_hook_entries *p;
+
+ p = rcu_dereference_raw(*pp);
+ if (nf_remove_net_hook(p, reg)) {
+ p = __nf_hook_entries_try_shrink(p, pp);
+ nf_hook_entries_free(p);
+ }
+}
+EXPORT_SYMBOL_GPL(nf_hook_entries_delete_raw);
+
int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg)
{
int err;
diff --git a/net/netfilter/nf_internals.h b/net/netfilter/nf_internals.h
index 18f6d7ae995b..e15779fd58e3 100644
--- a/net/netfilter/nf_internals.h
+++ b/net/netfilter/nf_internals.h
@@ -15,4 +15,9 @@ void nf_queue_nf_hook_drop(struct net *net);
/* nf_log.c */
int __init netfilter_log_init(void);
+/* core.c */
+void nf_hook_entries_delete_raw(struct nf_hook_entries __rcu **pp,
+ const struct nf_hook_ops *reg);
+int nf_hook_entries_insert_raw(struct nf_hook_entries __rcu **pp,
+ const struct nf_hook_ops *reg);
#endif
--
2.11.0
--
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