Merge branch 'nf-ingress'

Pablo Neira Ayuso says:

====================
Netfilter ingress support (v4)

This is the v4 round of patches to add the Netfilter ingress hook, it basically
comes in two steps:

1) Add the CONFIG_NET_INGRESS switch to wrap the ingress static key around it.
   The idea is to use the same global static key to avoid adding more code to
   the hot path.

2) Add the Netfilter ingress hook after the tc ingress hook, under the global
   ingress_needed static key. As I said, the netfilter ingress hook also has
   its own static key, that is nested under the global static key. Please, see
   patch 5/5 for performance numbers and more information.

I originally started this next round, as it was suggested, exploring the
independent static key for netfilter ingress just after tc ingress, but the
results that I gathered from that patch are not good for non-users:

Result: OK: 6425927(c6425843+d83) usec, 100000000 (60byte,0frags)
  15561955pps 7469Mb/sec (7469738400bps) errors: 100000000

this roughly means 500Kpps less performance wrt. the base numbers, so that's
the reason why I discarded that approach and I focused on this.

The idea of this patchset is to open the window to nf_tables, which comes with
features that will work out-of-the-box (once the boiler plate code to support
the 'netdev' table family is in place), to avoid repeating myself [1], the most
relevant features are:

1) Multi-dimensional key dictionary lookups.
2) Arbitrary stateful flow tables.
3) Transactions and good support for dynamic updates.

But there are also interest aspects to consider from userspace, such as the
ability to support new layer 2 protocols without kernel updates, a well-defined
netlink interface, userspace libraries and utilities for third party
applications, among others.

I hope we can be happy with this approach.

Please, apply. Thanks.

[1] http://marc.info/?l=netfilter-devel&m=143033337020328&w=2
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 40 insertions, 3 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index af549062ae8e7..29f0d6e6542c6 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -135,6 +135,7 @@
 #include <linux/if_macvlan.h>
 #include <linux/errqueue.h>
 #include <linux/hrtimer.h>
+#include <linux/netfilter_ingress.h>
 
 #include "net-sysfs.h"
 
@@ -1630,7 +1631,7 @@ int call_netdevice_notifiers(unsigned long val, struct net_device *dev)
 }
 EXPORT_SYMBOL(call_netdevice_notifiers);
 
-#ifdef CONFIG_NET_CLS_ACT
+#ifdef CONFIG_NET_INGRESS
 static struct static_key ingress_needed __read_mostly;
 
 void net_inc_ingress_queue(void)
@@ -3666,6 +3667,13 @@ static inline struct sk_buff *handle_ing(struct sk_buff *skb,
 
 	return skb;
 }
+#else
+static inline struct sk_buff *handle_ing(struct sk_buff *skb,
+					 struct packet_type **pt_prev,
+					 int *ret, struct net_device *orig_dev)
+{
+	return skb;
+}
 #endif
 
 /**
@@ -3739,6 +3747,28 @@ static bool skb_pfmemalloc_protocol(struct sk_buff *skb)
 	}
 }
 
+#ifdef CONFIG_NETFILTER_INGRESS
+static inline int nf_ingress(struct sk_buff *skb, struct packet_type **pt_prev,
+			     int *ret, struct net_device *orig_dev)
+{
+	if (nf_hook_ingress_active(skb)) {
+		if (*pt_prev) {
+			*ret = deliver_skb(skb, *pt_prev, orig_dev);
+			*pt_prev = NULL;
+		}
+
+		return nf_hook_ingress(skb);
+	}
+	return 0;
+}
+#else
+static inline int nf_ingress(struct sk_buff *skb, struct packet_type **pt_prev,
+			     int *ret, struct net_device *orig_dev)
+{
+	return 0;
+}
+#endif
+
 static int __netif_receive_skb_core(struct sk_buff *skb, bool pfmemalloc)
 {
 	struct packet_type *ptype, *pt_prev;
@@ -3798,13 +3828,17 @@ another_round:
 	}
 
 skip_taps:
-#ifdef CONFIG_NET_CLS_ACT
+#ifdef CONFIG_NET_INGRESS
 	if (static_key_false(&ingress_needed)) {
 		skb = handle_ing(skb, &pt_prev, &ret, orig_dev);
 		if (!skb)
 			goto unlock;
-	}
 
+		if (nf_ingress(skb, &pt_prev, &ret, orig_dev) < 0)
+			goto unlock;
+	}
+#endif
+#ifdef CONFIG_NET_CLS_ACT
 	skb->tc_verd = 0;
 ncls:
 #endif
@@ -6967,6 +7001,9 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
 	dev->group = INIT_NETDEV_GROUP;
 	if (!dev->ethtool_ops)
 		dev->ethtool_ops = &default_ethtool_ops;
+
+	nf_hook_ingress_init(dev);
+
 	return dev;
 
 free_all: