netfilter: Generalize ingress hook

Prepare for addition of a netfilter egress hook by generalizing the
ingress hook introduced by commit e687ad60af09 ("netfilter: add
netfilter ingress hook after handle_ing() under unique static key").

In particular, rename and refactor the ingress hook's static inlines
such that they can be reused for an egress hook.

No functional change intended.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/include/linux/netfilter_netdev.h b/include/linux/netfilter_netdev.h
index a13774b..49e2647 100644 (file)
--- a/include/linux/netfilter_netdev.h
+++ b/include/linux/netfilter_netdev.h
@@ -1,34 +1,37 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _NETFILTER_INGRESS_H_
-#define _NETFILTER_INGRESS_H_
+#ifndef _NETFILTER_NETDEV_H_
+#define _NETFILTER_NETDEV_H_
 
 #include <linux/netfilter.h>
 #include <linux/netdevice.h>
 
-#ifdef CONFIG_NETFILTER_INGRESS
-static inline bool nf_hook_ingress_active(const struct sk_buff *skb)
+#ifdef CONFIG_NETFILTER
+static __always_inline bool nf_hook_netdev_active(enum nf_dev_hooks hooknum,
+                                         struct nf_hook_entries __rcu *hooks)
 {
 #ifdef CONFIG_JUMP_LABEL
-       if (!static_key_false(&nf_hooks_needed[NFPROTO_NETDEV][NF_NETDEV_INGRESS]))
+       if (!static_key_false(&nf_hooks_needed[NFPROTO_NETDEV][hooknum]))
                return false;
 #endif
-       return rcu_access_pointer(skb->dev->nf_hooks_ingress);
+       return rcu_access_pointer(hooks);
 }
 
 /* caller must hold rcu_read_lock */
-static inline int nf_hook_ingress(struct sk_buff *skb)
+static __always_inline int nf_hook_netdev(struct sk_buff *skb,
+                                         enum nf_dev_hooks hooknum,
+                                         struct nf_hook_entries __rcu *hooks)
 {
-       struct nf_hook_entries *e = rcu_dereference(skb->dev->nf_hooks_ingress);
+       struct nf_hook_entries *e = rcu_dereference(hooks);
        struct nf_hook_state state;
        int ret;
 
-       /* Must recheck the ingress hook head, in the event it became NULL
-        * after the check in nf_hook_ingress_active evaluated to true.
+       /* Must recheck the hook head, in the event it became NULL
+        * after the check in nf_hook_netdev_active evaluated to true.
         */
        if (unlikely(!e))
                return 0;
 
-       nf_hook_state_init(&state, NF_NETDEV_INGRESS,
+       nf_hook_state_init(&state, hooknum,
                           NFPROTO_NETDEV, skb->dev, NULL, NULL,
                           dev_net(skb->dev), NULL);
        ret = nf_hook_slow(skb, &state, e, 0);
@@ -37,10 +40,26 @@ static inline int nf_hook_ingress(struct sk_buff *skb)
 
        return ret;
 }
+#endif /* CONFIG_NETFILTER */
 
-static inline void nf_hook_ingress_init(struct net_device *dev)
+static inline void nf_hook_netdev_init(struct net_device *dev)
 {
+#ifdef CONFIG_NETFILTER_INGRESS
        RCU_INIT_POINTER(dev->nf_hooks_ingress, NULL);
+#endif
+}
+
+#ifdef CONFIG_NETFILTER_INGRESS
+static inline bool nf_hook_ingress_active(const struct sk_buff *skb)
+{
+       return nf_hook_netdev_active(NF_NETDEV_INGRESS,
+                                    skb->dev->nf_hooks_ingress);
+}
+
+static inline int nf_hook_ingress(struct sk_buff *skb)
+{
+       return nf_hook_netdev(skb, NF_NETDEV_INGRESS,
+                             skb->dev->nf_hooks_ingress);
 }
 #else /* CONFIG_NETFILTER_INGRESS */
 static inline int nf_hook_ingress_active(struct sk_buff *skb)
@@ -52,7 +71,5 @@ static inline int nf_hook_ingress(struct sk_buff *skb)
 {
        return 0;
 }
-
-static inline void nf_hook_ingress_init(struct net_device *dev) {}
 #endif /* CONFIG_NETFILTER_INGRESS */
 #endif /* _NETFILTER_INGRESS_H_ */

diff --git a/net/core/dev.c b/net/core/dev.c
index b1ce1c9..13d562f 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -9846,7 +9846,7 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
        if (!dev->ethtool_ops)
                dev->ethtool_ops = &default_ethtool_ops;
 
-       nf_hook_ingress_init(dev);
+       nf_hook_netdev_init(dev);
 
        return dev;