Merge branch 'connection-tracking-support-for-bridge'

Pablo Neira Ayuso says:

====================
connection tracking support for bridge

This patchset adds native connection tracking support for the bridge.

Patch #1 and #2 extract code from IPv4/IPv6 fragmentation core and
introduce the fraglist splitter. That splits a skbuff fraglist into
independent fragments.

Patch #3 and #4 also extract code from IPv4/IPv6 fragmentation core
and introduce the skbuff into fragments transformer. This can be used
by linearized skbuffs (eg. coming from nfqueue and ct helpers) as well
as cloned skbuffs (that are either seen either with taps or with bridge
port flooding).

Patch #5 moves the specific IPCB() code from these new fragment
splitter/transformer APIs into the IPv4 stack. The bridge has a
different control buffer layout and it starts using this new APIs in
this patchset.

Patch #6 adds basic infrastructure that allows to register bridge
conntrack support.

Patch #7 adds bridge conntrack support (only for IPv4 in this patch).

Patch #8 adds IPv6 support for the bridge conntrack support.

Patch #9 registers the IPv4/IPv6 conntrack hooks in case the bridge
conntrack is used to deal with local traffic, ie. prerouting -> input
bridge hook path. This cover the bridge interface has a IP address
scenario.

Before this patchset, only chance for people to do stateful filtering is
to use the `br_netfilter` emulation layer, that turns bridge frame into
IPv4/IPv6 packets and inject them into the IPv4/IPv6 hooks. Apparently,
this module allows users to use iptables and all of its feature-set from
the bridge, including stateful filtering. However, this approach is
flawed in many aspects that have been discussed many times. This is a
step forward to deprecate `br_netfilter'.

v2: Fix English typo in commit message.
v3: Fix another English typo in commit message.
====================

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

1 files changed, 50 insertions, 0 deletions

diff --git a/include/linux/netfilter_ipv6.h b/include/linux/netfilter_ipv6.h
index 12113e502656..a21b8c9623ee 100644
--- a/include/linux/netfilter_ipv6.h
+++ b/include/linux/netfilter_ipv6.h
@@ -19,6 +19,7 @@ struct ip6_rt_info {
 };
 
 struct nf_queue_entry;
+struct nf_ct_bridge_frag_data;
 
 /*
  * Hook functions for ipv6 to allow xt_* modules to be built-in even
@@ -39,6 +40,15 @@ struct nf_ipv6_ops {
 	int (*fragment)(struct net *net, struct sock *sk, struct sk_buff *skb,
 			int (*output)(struct net *, struct sock *, struct sk_buff *));
 	int (*reroute)(struct sk_buff *skb, const struct nf_queue_entry *entry);
+#if IS_MODULE(CONFIG_IPV6)
+	int (*br_defrag)(struct net *net, struct sk_buff *skb, u32 user);
+	int (*br_fragment)(struct net *net, struct sock *sk,
+			   struct sk_buff *skb,
+			   struct nf_ct_bridge_frag_data *data,
+			   int (*output)(struct net *, struct sock *sk,
+					 const struct nf_ct_bridge_frag_data *data,
+					 struct sk_buff *));
+#endif
 };
 
 #ifdef CONFIG_NETFILTER
@@ -86,6 +96,46 @@ static inline int nf_ip6_route(struct net *net, struct dst_entry **dst,
 #endif
 }
 
+static inline int nf_ipv6_br_defrag(struct net *net, struct sk_buff *skb,
+				    u32 user)
+{
+#if IS_MODULE(CONFIG_IPV6)
+	const struct nf_ipv6_ops *v6_ops = nf_get_ipv6_ops();
+
+	if (!v6_ops)
+		return 1;
+
+	return v6_ops->br_defrag(net, skb, user);
+#else
+	return nf_ct_frag6_gather(net, skb, user);
+#endif
+}
+
+int br_ip6_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
+		    struct nf_ct_bridge_frag_data *data,
+		    int (*output)(struct net *, struct sock *sk,
+				  const struct nf_ct_bridge_frag_data *data,
+				  struct sk_buff *));
+
+static inline int nf_br_ip6_fragment(struct net *net, struct sock *sk,
+				     struct sk_buff *skb,
+				     struct nf_ct_bridge_frag_data *data,
+				     int (*output)(struct net *, struct sock *sk,
+						   const struct nf_ct_bridge_frag_data *data,
+						   struct sk_buff *))
+{
+#if IS_MODULE(CONFIG_IPV6)
+	const struct nf_ipv6_ops *v6_ops = nf_get_ipv6_ops();
+
+	if (!v6_ops)
+		return 1;
+
+	return v6_ops->br_fragment(net, sk, skb, data, output);
+#else
+	return br_ip6_fragment(net, sk, skb, data, output);
+#endif
+}
+
 int ip6_route_me_harder(struct net *net, struct sk_buff *skb);
 
 static inline int nf_ip6_route_me_harder(struct net *net, struct sk_buff *skb)