netfilter: nf_tables_inet: don't use multihook infrastructure anymore

Use new native NFPROTO_INET support in netfilter core, this gets rid of
ad-hoc code in the nf_tables API codebase.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/net/netfilter/nf_tables_ipv4.h

@@ -53,6 +53,4 @@ static inline void nft_set_pktinfo_ipv4_validate(struct nft_pktinfo *pkt,
 		nft_set_pktinfo_unspec(pkt, skb);
 }
 
-extern struct nft_af_info nft_af_ipv4;
-
 #endif

include/net/netfilter/nf_tables_ipv6.h

@@ -69,6 +69,4 @@ static inline void nft_set_pktinfo_ipv6_validate(struct nft_pktinfo *pkt,
 		nft_set_pktinfo_unspec(pkt, skb);
 }
 
-extern struct nft_af_info nft_af_ipv6;
-
 #endif

net/ipv4/netfilter/nf_tables_ipv4.c

@@ -45,7 +45,7 @@ static unsigned int nft_ipv4_output(void *priv,
 	return nft_do_chain_ipv4(priv, skb, state);
 }
 
-struct nft_af_info nft_af_ipv4 __read_mostly = {
+static struct nft_af_info nft_af_ipv4 __read_mostly = {
 	.family		= NFPROTO_IPV4,
 	.nhooks		= NF_INET_NUMHOOKS,
 	.owner		= THIS_MODULE,
@@ -58,7 +58,6 @@ struct nft_af_info nft_af_ipv4 __read_mostly = {
 		[NF_INET_POST_ROUTING]	= nft_do_chain_ipv4,
 	},
 };
-EXPORT_SYMBOL_GPL(nft_af_ipv4);
 
 static int nf_tables_ipv4_init_net(struct net *net)
 {

net/ipv6/netfilter/nf_tables_ipv6.c

@@ -42,7 +42,7 @@ static unsigned int nft_ipv6_output(void *priv,
 	return nft_do_chain_ipv6(priv, skb, state);
 }
 
-struct nft_af_info nft_af_ipv6 __read_mostly = {
+static struct nft_af_info nft_af_ipv6 __read_mostly = {
 	.family		= NFPROTO_IPV6,
 	.nhooks		= NF_INET_NUMHOOKS,
 	.owner		= THIS_MODULE,
@@ -55,7 +55,6 @@ struct nft_af_info nft_af_ipv6 __read_mostly = {
 		[NF_INET_POST_ROUTING]	= nft_do_chain_ipv6,
 	},
 };
-EXPORT_SYMBOL_GPL(nft_af_ipv6);
 
 static int nf_tables_ipv6_init_net(struct net *net)
 {

net/netfilter/nf_tables_inet.c

@@ -9,6 +9,7 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/ip.h>
+#include <linux/ipv6.h>
 #include <linux/netfilter_ipv4.h>
 #include <linux/netfilter_ipv6.h>
 #include <net/netfilter/nf_tables.h>
@@ -16,26 +17,71 @@
 #include <net/netfilter/nf_tables_ipv6.h>
 #include <net/ip.h>
 
-static void nft_inet_hook_ops_init(struct nf_hook_ops *ops, unsigned int n)
+static unsigned int nft_do_chain_inet(void *priv, struct sk_buff *skb,
+				      const struct nf_hook_state *state)
 {
-	struct nft_af_info *afi;
-
-	if (n == 1)
-		afi = &nft_af_ipv4;
-	else
-		afi = &nft_af_ipv6;
+	struct nft_pktinfo pkt;
+
+	nft_set_pktinfo(&pkt, skb, state);
+
+	switch (state->pf) {
+	case NFPROTO_IPV4:
+		nft_set_pktinfo_ipv4(&pkt, skb);
+		break;
+	case NFPROTO_IPV6:
+		nft_set_pktinfo_ipv6(&pkt, skb);
+		break;
+	default:
+		break;
+	}
+
+	return nft_do_chain(&pkt, priv);
+}
 
-	ops->pf = afi->family;
-	if (afi->hooks[ops->hooknum])
-		ops->hook = afi->hooks[ops->hooknum];
+static unsigned int nft_inet_output(void *priv, struct sk_buff *skb,
+				    const struct nf_hook_state *state)
+{
+	struct nft_pktinfo pkt;
+
+	nft_set_pktinfo(&pkt, skb, state);
+
+	switch (state->pf) {
+	case NFPROTO_IPV4:
+		if (unlikely(skb->len < sizeof(struct iphdr) ||
+			     ip_hdr(skb)->ihl < sizeof(struct iphdr) / 4)) {
+			if (net_ratelimit())
+				pr_info("ignoring short SOCK_RAW packet\n");
+			return NF_ACCEPT;
+		}
+		nft_set_pktinfo_ipv4(&pkt, skb);
+		break;
+	case NFPROTO_IPV6:
+	        if (unlikely(skb->len < sizeof(struct ipv6hdr))) {
+			if (net_ratelimit())
+				pr_info("ignoring short SOCK_RAW packet\n");
+			return NF_ACCEPT;
+		}
+		nft_set_pktinfo_ipv6(&pkt, skb);
+		break;
+	default:
+		break;
+	}
+
+	return nft_do_chain(&pkt, priv);
 }
 
 static struct nft_af_info nft_af_inet __read_mostly = {
 	.family		= NFPROTO_INET,
 	.nhooks		= NF_INET_NUMHOOKS,
 	.owner		= THIS_MODULE,
-	.nops		= 2,
-	.hook_ops_init	= nft_inet_hook_ops_init,
+	.nops		= 1,
+	.hooks		= {
+		[NF_INET_LOCAL_IN]	= nft_do_chain_inet,
+		[NF_INET_LOCAL_OUT]	= nft_inet_output,
+		[NF_INET_FORWARD]	= nft_do_chain_inet,
+		[NF_INET_PRE_ROUTING]	= nft_do_chain_inet,
+		[NF_INET_POST_ROUTING]	= nft_do_chain_inet,
+        },
 };
 
 static int __net_init nf_tables_inet_init_net(struct net *net)