kernel: generic: Fix nftables inet table breakage

Commit b7265c59ab7d ("kernel: backport a series of netfilter cleanup
patches to 4.14") added patch 302-netfilter-nf_tables_inet-don-t-use-
multihook-infrast.patch.  That patch switches the netfilter core in the
kernel to use the new native NFPROTO_INET support.  Unfortunately, the
new native NFPROTO_INET support does not exist in 4.14 and was not
backported along with this patchset.  As such, nftables inet tables never
see any traffic.

As an example the following nft counter rule should increment for every
packet coming into the box, but never will:

nft add table inet foo
nft add chain inet foo bar { type filter hook input priority 0\; }
nft add rule inet foo bar counter

This commit pulls in the required backport patches to add the new
native NFPROTO_INET support, and thus restore nftables inet table
functionality.

Tested on Turris Omnia (mvebu)

Fixes: b7265c59ab7d ("kernel: backport a series of netfilter cleanup ...")
Signed-off-by: Brett Mastbergen <bmastbergen@untangle.com>

1 files changed, 95 insertions, 0 deletions

diff --git a/target/linux/generic/backport-4.14/294-v4.16-netfilter-reduce-hook-array-sizes-to-what-is-needed.patch b/target/linux/generic/backport-4.14/294-v4.16-netfilter-reduce-hook-array-sizes-to-what-is-needed.patch
new file mode 100644
index 0000000000..d9009b8e1f
--- /dev/null
+++ b/target/linux/generic/backport-4.14/294-v4.16-netfilter-reduce-hook-array-sizes-to-what-is-needed.patch
@@ -0,0 +1,95 @@
+From ef57170bbfdd6958281011332b1fd237712f69f0 Mon Sep 17 00:00:00 2001
+From: Florian Westphal <fw@strlen.de>
+Date: Thu, 7 Dec 2017 16:28:24 +0100
+Subject: [PATCH 06/11] netfilter: reduce hook array sizes to what is needed
+
+Not all families share the same hook count, adjust sizes to what is
+needed.
+
+struct net before:
+/* size: 6592, cachelines: 103, members: 46 */
+after:
+/* size: 5952, cachelines: 93, members: 46 */
+
+Signed-off-by: Florian Westphal <fw@strlen.de>
+Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
+---
+ include/net/netns/netfilter.h | 10 +++++-----
+ net/netfilter/core.c          | 24 +++++++++++++++++-------
+ 2 files changed, 22 insertions(+), 12 deletions(-)
+
+--- a/include/net/netns/netfilter.h
++++ b/include/net/netns/netfilter.h
+@@ -17,11 +17,11 @@ struct netns_nf {
+ #ifdef CONFIG_SYSCTL
+ 	struct ctl_table_header *nf_log_dir_header;
+ #endif
+-	struct nf_hook_entries __rcu *hooks_ipv4[NF_MAX_HOOKS];
+-	struct nf_hook_entries __rcu *hooks_ipv6[NF_MAX_HOOKS];
+-	struct nf_hook_entries __rcu *hooks_arp[NF_MAX_HOOKS];
+-	struct nf_hook_entries __rcu *hooks_bridge[NF_MAX_HOOKS];
+-	struct nf_hook_entries __rcu *hooks_decnet[NF_MAX_HOOKS];
++	struct nf_hook_entries __rcu *hooks_ipv4[NF_INET_NUMHOOKS];
++	struct nf_hook_entries __rcu *hooks_ipv6[NF_INET_NUMHOOKS];
++	struct nf_hook_entries __rcu *hooks_arp[NF_ARP_NUMHOOKS];
++	struct nf_hook_entries __rcu *hooks_bridge[NF_INET_NUMHOOKS];
++	struct nf_hook_entries __rcu *hooks_decnet[NF_DN_NUMHOOKS];
+ #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV4)
+ 	bool			defrag_ipv4;
+ #endif
+--- a/net/netfilter/core.c
++++ b/net/netfilter/core.c
+@@ -268,14 +268,24 @@ static struct nf_hook_entries __rcu **nf
+ 	case NFPROTO_NETDEV:
+ 		break;
+ 	case NFPROTO_ARP:
++		if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_arp) <= reg->hooknum))
++			return NULL;
+ 		return net->nf.hooks_arp + reg->hooknum;
+ 	case NFPROTO_BRIDGE:
++		if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_bridge) <= reg->hooknum))
++			return NULL;
+ 		return net->nf.hooks_bridge + reg->hooknum;
+ 	case NFPROTO_IPV4:
++		if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_ipv4) <= reg->hooknum))
++			return NULL;
+ 		return net->nf.hooks_ipv4 + reg->hooknum;
+ 	case NFPROTO_IPV6:
++		if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_ipv6) <= reg->hooknum))
++			return NULL;
+ 		return net->nf.hooks_ipv6 + reg->hooknum;
+ 	case NFPROTO_DECNET:
++		if (WARN_ON_ONCE(ARRAY_SIZE(net->nf.hooks_decnet) <= reg->hooknum))
++			return NULL;
+ 		return net->nf.hooks_decnet + reg->hooknum;
+ 	default:
+ 		WARN_ON_ONCE(1);
+@@ -549,21 +559,21 @@ void (*nf_nat_decode_session_hook)(struc
+ EXPORT_SYMBOL(nf_nat_decode_session_hook);
+ #endif
+ 
+-static void __net_init __netfilter_net_init(struct nf_hook_entries *e[NF_MAX_HOOKS])
++static void __net_init __netfilter_net_init(struct nf_hook_entries **e, int max)
+ {
+ 	int h;
+ 
+-	for (h = 0; h < NF_MAX_HOOKS; h++)
++	for (h = 0; h < max; h++)
+ 		RCU_INIT_POINTER(e[h], NULL);
+ }
+ 
+ static int __net_init netfilter_net_init(struct net *net)
+ {
+-	__netfilter_net_init(net->nf.hooks_ipv4);
+-	__netfilter_net_init(net->nf.hooks_ipv6);
+-	__netfilter_net_init(net->nf.hooks_arp);
+-	__netfilter_net_init(net->nf.hooks_bridge);
+-	__netfilter_net_init(net->nf.hooks_decnet);
++	__netfilter_net_init(net->nf.hooks_ipv4, ARRAY_SIZE(net->nf.hooks_ipv4));
++	__netfilter_net_init(net->nf.hooks_ipv6, ARRAY_SIZE(net->nf.hooks_ipv6));
++	__netfilter_net_init(net->nf.hooks_arp, ARRAY_SIZE(net->nf.hooks_arp));
++	__netfilter_net_init(net->nf.hooks_bridge, ARRAY_SIZE(net->nf.hooks_bridge));
++	__netfilter_net_init(net->nf.hooks_decnet, ARRAY_SIZE(net->nf.hooks_decnet));
+ 
+ #ifdef CONFIG_PROC_FS
+ 	net->nf.proc_netfilter = proc_net_mkdir(net, "netfilter",