netfilter: nf_tables: add compatibility layer for x_tables

This patch adds the x_tables compatibility layer. This allows you
to use existing x_tables matches and targets from nf_tables.

This compatibility later allows us to use existing matches/targets
for features that are still missing in nf_tables. We can progressively
replace them with native nf_tables extensions. It also provides the
userspace compatibility software that allows you to express the
rule-set using the iptables syntax but using the nf_tables kernel
components.

In order to get this compatibility layer working, I've done the
following things:

* add NFNL_SUBSYS_NFT_COMPAT: this new nfnetlink subsystem is used
to query the x_tables match/target revision, so we don't need to
use the native x_table getsockopt interface.

* emulate xt structures: this required extending the struct nft_pktinfo
to include the fragment offset, which is already obtained from
ip[6]_tables and that is used by some matches/targets.

* add support for default policy to base chains, required to emulate
  x_tables.

* add NFTA_CHAIN_USE attribute to obtain the number of references to
  chains, required by x_tables emulation.

* add chain packet/byte counters using per-cpu.

* support 32-64 bits compat.

For historical reasons, this patch includes the following patches
that were posted in the netfilter-devel mailing list.

From Pablo Neira Ayuso:
* nf_tables: add default policy to base chains
* netfilter: nf_tables: add NFTA_CHAIN_USE attribute
* nf_tables: nft_compat: private data of target and matches in contiguous area
* nf_tables: validate hooks for compat match/target
* nf_tables: nft_compat: release cached matches/targets
* nf_tables: x_tables support as a compile time option
* nf_tables: fix alias for xtables over nftables module
* nf_tables: add packet and byte counters per chain
* nf_tables: fix per-chain counter stats if no counters are passed
* nf_tables: don't bump chain stats
* nf_tables: add protocol and flags for xtables over nf_tables
* nf_tables: add ip[6]t_entry emulation
* nf_tables: move specific layer 3 compat code to nf_tables_ipv[4|6]
* nf_tables: support 32bits-64bits x_tables compat
* nf_tables: fix compilation if CONFIG_COMPAT is disabled

From Patrick McHardy:
* nf_tables: move policy to struct nft_base_chain
* nf_tables: send notifications for base chain policy changes

From Alexander Primak:
* nf_tables: remove the duplicate NF_INET_LOCAL_OUT

From Nicolas Dichtel:
* nf_tables: fix compilation when nf-netlink is a module
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/net/netfilter/nf_tables.h

@@ -3,6 +3,7 @@
 
 #include <linux/list.h>
 #include <linux/netfilter.h>
+#include <linux/netfilter/x_tables.h>
 #include <linux/netfilter/nf_tables.h>
 #include <net/netlink.h>
 
@@ -15,8 +16,23 @@ struct nft_pktinfo {
 	u8				hooknum;
 	u8				nhoff;
 	u8				thoff;
+	/* for x_tables compatibility */
+	struct xt_action_param		xt;
 };
 
+static inline void nft_set_pktinfo(struct nft_pktinfo *pkt,
+				   const struct nf_hook_ops *ops,
+				   struct sk_buff *skb,
+				   const struct net_device *in,
+				   const struct net_device *out)
+{
+	pkt->skb = skb;
+	pkt->in = pkt->xt.in = in;
+	pkt->out = pkt->xt.out = out;
+	pkt->hooknum = pkt->xt.hooknum = ops->hooknum;
+	pkt->xt.family = ops->pf;
+}
+
 struct nft_data {
 	union {
 		u32				data[4];
@@ -57,6 +73,7 @@ static inline void nft_data_debug(const struct nft_data *data)
  * 	@afi: address family info
  * 	@table: the table the chain is contained in
  * 	@chain: the chain the rule is contained in
+ *	@nla: netlink attributes
  */
 struct nft_ctx {
 	const struct sk_buff		*skb;
@@ -64,6 +81,7 @@ struct nft_ctx {
 	const struct nft_af_info	*afi;
 	const struct nft_table		*table;
 	const struct nft_chain		*chain;
+	const struct nlattr * const 	*nla;
 };
 
 struct nft_data_desc {
@@ -235,7 +253,8 @@ extern void nf_tables_unbind_set(const struct nft_ctx *ctx, struct nft_set *set,
  *	@maxattr: highest netlink attribute number
  */
 struct nft_expr_type {
-	const struct nft_expr_ops	*(*select_ops)(const struct nlattr * const tb[]);
+	const struct nft_expr_ops	*(*select_ops)(const struct nft_ctx *,
+						       const struct nlattr * const tb[]);
 	const struct nft_expr_ops	*ops;
 	struct list_head		list;
 	const char			*name;
@@ -253,6 +272,8 @@ struct nft_expr_type {
  *	@destroy: destruction function
  *	@dump: function to dump parameters
  *	@type: expression type
+ *	@validate: validate expression, called during loop detection
+ *	@data: extra data to attach to this expression operation
  */
 struct nft_expr;
 struct nft_expr_ops {
@@ -267,8 +288,11 @@ struct nft_expr_ops {
 	void				(*destroy)(const struct nft_expr *expr);
 	int				(*dump)(struct sk_buff *skb,
 						const struct nft_expr *expr);
-	const struct nft_data *		(*get_verdict)(const struct nft_expr *expr);
+	int				(*validate)(const struct nft_ctx *ctx,
+						    const struct nft_expr *expr,
+						    const struct nft_data **data);
 	const struct nft_expr_type	*type;
+	void				*data;
 };
 
 #define NFT_EXPR_MAXATTR		16
@@ -368,16 +392,25 @@ enum nft_chain_type {
 	NFT_CHAIN_T_MAX
 };
 
+struct nft_stats {
+	u64 bytes;
+	u64 pkts;
+};
+
 /**
  *	struct nft_base_chain - nf_tables base chain
  *
  *	@ops: netfilter hook ops
  *	@type: chain type
+ *	@policy: default policy
+ *	@stats: per-cpu chain stats
  *	@chain: the chain
  */
 struct nft_base_chain {
 	struct nf_hook_ops		ops;
 	enum nft_chain_type		type;
+	u8				policy;
+	struct nft_stats __percpu	*stats;
 	struct nft_chain		chain;
 };
 
@@ -386,11 +419,8 @@ static inline struct nft_base_chain *nft_base_chain(const struct nft_chain *chai
 	return container_of(chain, struct nft_base_chain, chain);
 }
 
-extern unsigned int nft_do_chain(const struct nf_hook_ops *ops,
-				 struct sk_buff *skb,
-				 const struct net_device *in,
-				 const struct net_device *out,
-				 int (*okfn)(struct sk_buff *));
+extern unsigned int nft_do_chain_pktinfo(struct nft_pktinfo *pkt,
+					 const struct nf_hook_ops *ops);
 
 /**
  *	struct nft_table - nf_tables table

include/net/netfilter/nf_tables_ipv4.h

+#ifndef _NF_TABLES_IPV4_H_
+#define _NF_TABLES_IPV4_H_
+
+#include <net/netfilter/nf_tables.h>
+#include <net/ip.h>
+
+static inline void
+nft_set_pktinfo_ipv4(struct nft_pktinfo *pkt,
+		     const struct nf_hook_ops *ops,
+		     struct sk_buff *skb,
+		     const struct net_device *in,
+		     const struct net_device *out)
+{
+	struct iphdr *ip;
+
+	nft_set_pktinfo(pkt, ops, skb, in, out);
+
+	pkt->xt.thoff = ip_hdrlen(pkt->skb);
+	ip = ip_hdr(pkt->skb);
+	pkt->xt.fragoff = ntohs(ip->frag_off) & IP_OFFSET;
+}
+
+#endif

include/net/netfilter/nf_tables_ipv6.h

+#ifndef _NF_TABLES_IPV6_H_
+#define _NF_TABLES_IPV6_H_
+
+#include <linux/netfilter_ipv6/ip6_tables.h>
+#include <net/ipv6.h>
+
+static inline int
+nft_set_pktinfo_ipv6(struct nft_pktinfo *pkt,
+		     const struct nf_hook_ops *ops,
+		     struct sk_buff *skb,
+		     const struct net_device *in,
+		     const struct net_device *out)
+{
+	int protohdr, thoff = 0;
+	unsigned short frag_off;
+
+	nft_set_pktinfo(pkt, ops, skb, in, out);
+
+	protohdr = ipv6_find_hdr(pkt->skb, &thoff, -1, &frag_off, NULL);
+	/* If malformed, drop it */
+	if (protohdr < 0)
+		return -1;
+
+	pkt->xt.thoff = thoff;
+	pkt->xt.fragoff = frag_off;
+
+	return 0;
+}
+
+#endif

include/uapi/linux/netfilter/Kbuild

@@ -6,6 +6,7 @@ header-y += nf_conntrack_sctp.h
 header-y += nf_conntrack_tcp.h
 header-y += nf_conntrack_tuple_common.h
 header-y += nf_tables.h
+header-y += nf_tables_compat.h
 header-y += nf_nat.h
 header-y += nfnetlink.h
 header-y += nfnetlink_acct.h

include/uapi/linux/netfilter/nf_tables.h

@@ -115,7 +115,10 @@ enum nft_table_attributes {
  * @NFTA_CHAIN_HANDLE: numeric handle of the chain (NLA_U64)
  * @NFTA_CHAIN_NAME: name of the chain (NLA_STRING)
  * @NFTA_CHAIN_HOOK: hook specification for basechains (NLA_NESTED: nft_hook_attributes)
+ * @NFTA_CHAIN_POLICY: numeric policy of the chain (NLA_U32)
+ * @NFTA_CHAIN_USE: number of references to this chain (NLA_U32)
  * @NFTA_CHAIN_TYPE: type name of the string (NLA_NUL_STRING)
+ * @NFTA_CHAIN_COUNTERS: counter specification of the chain (NLA_NESTED: nft_counter_attributes)
  */
 enum nft_chain_attributes {
 	NFTA_CHAIN_UNSPEC,
@@ -123,7 +126,10 @@ enum nft_chain_attributes {
 	NFTA_CHAIN_HANDLE,
 	NFTA_CHAIN_NAME,
 	NFTA_CHAIN_HOOK,
+	NFTA_CHAIN_POLICY,
+	NFTA_CHAIN_USE,
 	NFTA_CHAIN_TYPE,
+	NFTA_CHAIN_COUNTERS,
 	__NFTA_CHAIN_MAX
 };
 #define NFTA_CHAIN_MAX		(__NFTA_CHAIN_MAX - 1)
@@ -135,6 +141,7 @@ enum nft_chain_attributes {
  * @NFTA_RULE_CHAIN: name of the chain containing the rule (NLA_STRING)
  * @NFTA_RULE_HANDLE: numeric handle of the rule (NLA_U64)
  * @NFTA_RULE_EXPRESSIONS: list of expressions (NLA_NESTED: nft_expr_attributes)
+ * @NFTA_RULE_COMPAT: compatibility specifications of the rule (NLA_NESTED: nft_rule_compat_attributes)
  */
 enum nft_rule_attributes {
 	NFTA_RULE_UNSPEC,
@@ -142,10 +149,35 @@ enum nft_rule_attributes {
 	NFTA_RULE_CHAIN,
 	NFTA_RULE_HANDLE,
 	NFTA_RULE_EXPRESSIONS,
+	NFTA_RULE_COMPAT,
 	__NFTA_RULE_MAX
 };
 #define NFTA_RULE_MAX		(__NFTA_RULE_MAX - 1)
 
+/**
+ * enum nft_rule_compat_flags - nf_tables rule compat flags
+ *
+ * @NFT_RULE_COMPAT_F_INV: invert the check result
+ */
+enum nft_rule_compat_flags {
+	NFT_RULE_COMPAT_F_INV	= (1 << 1),
+	NFT_RULE_COMPAT_F_MASK	= NFT_RULE_COMPAT_F_INV,
+};
+
+/**
+ * enum nft_rule_compat_attributes - nf_tables rule compat attributes
+ *
+ * @NFTA_RULE_COMPAT_PROTO: numerice value of handled protocol (NLA_U32)
+ * @NFTA_RULE_COMPAT_FLAGS: bitmask of enum nft_rule_compat_flags (NLA_U32)
+ */
+enum nft_rule_compat_attributes {
+	NFTA_RULE_COMPAT_UNSPEC,
+	NFTA_RULE_COMPAT_PROTO,
+	NFTA_RULE_COMPAT_FLAGS,
+	__NFTA_RULE_COMPAT_MAX
+};
+#define NFTA_RULE_COMPAT_MAX	(__NFTA_RULE_COMPAT_MAX - 1)
+
 /**
  * enum nft_set_flags - nf_tables set flags
  *

include/uapi/linux/netfilter/nf_tables_compat.h

+#ifndef _NFT_COMPAT_NFNETLINK_H_
+#define _NFT_COMPAT_NFNETLINK_H_
+
+enum nft_target_attributes {
+	NFTA_TARGET_UNSPEC,
+	NFTA_TARGET_NAME,
+	NFTA_TARGET_REV,
+	NFTA_TARGET_INFO,
+	__NFTA_TARGET_MAX
+};
+#define NFTA_TARGET_MAX		(__NFTA_TARGET_MAX - 1)
+
+enum nft_match_attributes {
+	NFTA_MATCH_UNSPEC,
+	NFTA_MATCH_NAME,
+	NFTA_MATCH_REV,
+	NFTA_MATCH_INFO,
+	__NFTA_MATCH_MAX
+};
+#define NFTA_MATCH_MAX		(__NFTA_MATCH_MAX - 1)
+
+#define NFT_COMPAT_NAME_MAX	32
+
+enum {
+	NFNL_MSG_COMPAT_GET,
+	NFNL_MSG_COMPAT_MAX
+};
+
+enum {
+	NFTA_COMPAT_UNSPEC = 0,
+	NFTA_COMPAT_NAME,
+	NFTA_COMPAT_REV,
+	NFTA_COMPAT_TYPE,
+	__NFTA_COMPAT_MAX,
+};
+#define NFTA_COMPAT_MAX (__NFTA_COMPAT_MAX - 1)
+
+#endif

include/uapi/linux/netfilter/nfnetlink.h

@@ -54,6 +54,7 @@ struct nfgenmsg {
 #define NFNL_SUBSYS_CTNETLINK_TIMEOUT	8
 #define NFNL_SUBSYS_CTHELPER		9
 #define NFNL_SUBSYS_NFTABLES		10
-#define NFNL_SUBSYS_COUNT		11
+#define NFNL_SUBSYS_NFT_COMPAT		11
+#define NFNL_SUBSYS_COUNT		12
 
 #endif /* _UAPI_NFNETLINK_H */

net/ipv4/netfilter/nf_tables_ipv4.c

@@ -15,6 +15,8 @@
 #include <linux/netfilter_ipv4.h>
 #include <net/netfilter/nf_tables.h>
 #include <net/ip.h>
+#include <net/net_namespace.h>
+#include <net/netfilter/nf_tables_ipv4.h>
 
 static unsigned int nft_ipv4_output(const struct nf_hook_ops *ops,
 				    struct sk_buff *skb,
@@ -22,6 +24,8 @@ static unsigned int nft_ipv4_output(const struct nf_hook_ops *ops,
 				    const struct net_device *out,
 				    int (*okfn)(struct sk_buff *))
 {
+	struct nft_pktinfo pkt;
+
 	if (unlikely(skb->len < sizeof(struct iphdr) ||
 		     ip_hdr(skb)->ihl < sizeof(struct iphdr) / 4)) {
 		if (net_ratelimit())
@@ -29,8 +33,9 @@ static unsigned int nft_ipv4_output(const struct nf_hook_ops *ops,
 				"packet\n");
 		return NF_ACCEPT;
 	}
+	nft_set_pktinfo_ipv4(&pkt, ops, skb, in, out);
 
-	return nft_do_chain(ops, skb, in, out, okfn);
+	return nft_do_chain_pktinfo(&pkt, ops);
 }
 
 static struct nft_af_info nft_af_ipv4 __read_mostly = {
@@ -42,6 +47,21 @@ static struct nft_af_info nft_af_ipv4 __read_mostly = {
 	},
 };
 
+
+static unsigned int
+nft_do_chain_ipv4(const struct nf_hook_ops *ops,
+		  struct sk_buff *skb,
+		  const struct net_device *in,
+		  const struct net_device *out,
+		  int (*okfn)(struct sk_buff *))
+{
+	struct nft_pktinfo pkt;
+
+	nft_set_pktinfo_ipv4(&pkt, ops, skb, in, out);
+
+	return nft_do_chain_pktinfo(&pkt, ops);
+}
+
 static struct nf_chain_type filter_ipv4 = {
 	.family		= NFPROTO_IPV4,
 	.name		= "filter",
@@ -52,11 +72,11 @@ static struct nf_chain_type filter_ipv4 = {
 			  (1 << NF_INET_PRE_ROUTING) |
 			  (1 << NF_INET_POST_ROUTING),
 	.fn		= {
-		[NF_INET_LOCAL_IN]	= nft_do_chain,
-		[NF_INET_LOCAL_OUT]	= nft_do_chain,
-		[NF_INET_FORWARD]	= nft_do_chain,
-		[NF_INET_PRE_ROUTING]	= nft_do_chain,
-		[NF_INET_POST_ROUTING]	= nft_do_chain,
+		[NF_INET_LOCAL_IN]	= nft_do_chain_ipv4,
+		[NF_INET_LOCAL_OUT]	= nft_ipv4_output,
+		[NF_INET_FORWARD]	= nft_do_chain_ipv4,
+		[NF_INET_PRE_ROUTING]	= nft_do_chain_ipv4,
+		[NF_INET_POST_ROUTING]	= nft_do_chain_ipv4,
 	},
 };
 

net/ipv4/netfilter/nft_chain_nat_ipv4.c

@@ -23,6 +23,7 @@
 #include <net/netfilter/nf_nat.h>
 #include <net/netfilter/nf_nat_core.h>
 #include <net/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables_ipv4.h>
 #include <net/netfilter/nf_nat_l3proto.h>
 #include <net/ip.h>
 
@@ -181,6 +182,7 @@ static unsigned int nf_nat_fn(const struct nf_hook_ops *ops,
 	struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
 	struct nf_conn_nat *nat;
 	enum nf_nat_manip_type maniptype = HOOK2MANIP(ops->hooknum);
+	struct nft_pktinfo pkt;
 	unsigned int ret;
 
 	if (ct == NULL || nf_ct_is_untracked(ct))
@@ -213,7 +215,9 @@ static unsigned int nf_nat_fn(const struct nf_hook_ops *ops,
 		if (nf_nat_initialized(ct, maniptype))
 			break;
 
-		ret = nft_do_chain(ops, skb, in, out, okfn);
+		nft_set_pktinfo_ipv4(&pkt, ops, skb, in, out);
+
+		ret = nft_do_chain_pktinfo(&pkt, ops);
 		if (ret != NF_ACCEPT)
 			return ret;
 		if (!nf_nat_initialized(ct, maniptype)) {

net/ipv4/netfilter/nft_chain_route_ipv4.c

@@ -17,6 +17,7 @@
 #include <linux/netfilter/nfnetlink.h>
 #include <linux/netfilter/nf_tables.h>
 #include <net/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables_ipv4.h>
 #include <net/route.h>
 #include <net/ip.h>
 
@@ -27,6 +28,7 @@ static unsigned int nf_route_table_hook(const struct nf_hook_ops *ops,
 					int (*okfn)(struct sk_buff *))
 {
 	unsigned int ret;
+	struct nft_pktinfo pkt;
 	u32 mark;
 	__be32 saddr, daddr;
 	u_int8_t tos;
@@ -37,13 +39,15 @@ static unsigned int nf_route_table_hook(const struct nf_hook_ops *ops,
 	    ip_hdrlen(skb) < sizeof(struct iphdr))
 		return NF_ACCEPT;
 
+	nft_set_pktinfo_ipv4(&pkt, ops, skb, in, out);
+
 	mark = skb->mark;
 	iph = ip_hdr(skb);
 	saddr = iph->saddr;
 	daddr = iph->daddr;
 	tos = iph->tos;
 
-	ret = nft_do_chain(ops, skb, in, out, okfn);
+	ret = nft_do_chain_pktinfo(&pkt, ops);
 	if (ret != NF_DROP && ret != NF_QUEUE) {
 		iph = ip_hdr(skb);
 

net/ipv6/netfilter/nf_tables_ipv6.c

@@ -14,6 +14,7 @@
 #include <linux/ipv6.h>
 #include <linux/netfilter_ipv6.h>
 #include <net/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables_ipv6.h>
 
 static unsigned int nft_ipv6_output(const struct nf_hook_ops *ops,
 				    struct sk_buff *skb,
@@ -21,14 +22,18 @@ static unsigned int nft_ipv6_output(const struct nf_hook_ops *ops,
 				    const struct net_device *out,
 				    int (*okfn)(struct sk_buff *))
 {
+	struct nft_pktinfo pkt;
+
 	if (unlikely(skb->len < sizeof(struct ipv6hdr))) {
 		if (net_ratelimit())
 			pr_info("nf_tables_ipv6: ignoring short SOCK_RAW "
 				"packet\n");
 		return NF_ACCEPT;
 	}
+	if (nft_set_pktinfo_ipv6(&pkt, ops, skb, in, out) < 0)
+		return NF_DROP;
 
-	return nft_do_chain(ops, skb, in, out, okfn);
+	return nft_do_chain_pktinfo(&pkt, ops);
 }
 
 static struct nft_af_info nft_af_ipv6 __read_mostly = {
@@ -40,6 +45,22 @@ static struct nft_af_info nft_af_ipv6 __read_mostly = {
 	},
 };
 
+static unsigned int
+nft_do_chain_ipv6(const struct nf_hook_ops *ops,
+		  struct sk_buff *skb,
+		  const struct net_device *in,
+		  const struct net_device *out,
+		  int (*okfn)(struct sk_buff *))
+{
+	struct nft_pktinfo pkt;
+
+	/* malformed packet, drop it */
+	if (nft_set_pktinfo_ipv6(&pkt, ops, skb, in, out) < 0)
+		return NF_DROP;
+
+	return nft_do_chain_pktinfo(&pkt, ops);
+}
+
 static struct nf_chain_type filter_ipv6 = {
 	.family		= NFPROTO_IPV6,
 	.name		= "filter",
@@ -50,11 +71,11 @@ static struct nf_chain_type filter_ipv6 = {
 			  (1 << NF_INET_PRE_ROUTING) |
 			  (1 << NF_INET_POST_ROUTING),
 	.fn		= {
-		[NF_INET_LOCAL_IN]	= nft_do_chain,
-		[NF_INET_LOCAL_OUT]	= nft_do_chain,
-		[NF_INET_FORWARD]	= nft_do_chain,
-		[NF_INET_PRE_ROUTING]	= nft_do_chain,
-		[NF_INET_POST_ROUTING]	= nft_do_chain,
+		[NF_INET_LOCAL_IN]	= nft_do_chain_ipv6,
+		[NF_INET_LOCAL_OUT]	= nft_ipv6_output,
+		[NF_INET_FORWARD]	= nft_do_chain_ipv6,
+		[NF_INET_PRE_ROUTING]	= nft_do_chain_ipv6,
+		[NF_INET_POST_ROUTING]	= nft_do_chain_ipv6,
 	},
 };
 

net/ipv6/netfilter/nft_chain_route_ipv6.c

@@ -19,6 +19,7 @@
 #include <linux/netfilter/nfnetlink.h>
 #include <linux/netfilter/nf_tables.h>
 #include <net/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables_ipv6.h>
 #include <net/route.h>
 
 static unsigned int nf_route_table_hook(const struct nf_hook_ops *ops,
@@ -28,10 +29,15 @@ static unsigned int nf_route_table_hook(const struct nf_hook_ops *ops,
 					int (*okfn)(struct sk_buff *))
 {
 	unsigned int ret;
+	struct nft_pktinfo pkt;
 	struct in6_addr saddr, daddr;
 	u_int8_t hop_limit;
 	u32 mark, flowlabel;
 
+	/* malformed packet, drop it */
+	if (nft_set_pktinfo_ipv6(&pkt, ops, skb, in, out) < 0)
+		return NF_DROP;
+
 	/* save source/dest address, mark, hoplimit, flowlabel, priority */
 	memcpy(&saddr, &ipv6_hdr(skb)->saddr, sizeof(saddr));
 	memcpy(&daddr, &ipv6_hdr(skb)->daddr, sizeof(daddr));
@@ -41,7 +47,7 @@ static unsigned int nf_route_table_hook(const struct nf_hook_ops *ops,
 	/* flowlabel and prio (includes version, which shouldn't change either */
 	flowlabel = *((u32 *)ipv6_hdr(skb));
 
-	ret = nft_do_chain(ops, skb, in, out, okfn);
+	ret = nft_do_chain_pktinfo(&pkt, ops);
 	if (ret != NF_DROP && ret != NF_QUEUE &&
 	    (memcmp(&ipv6_hdr(skb)->saddr, &saddr, sizeof(saddr)) ||
 	     memcmp(&ipv6_hdr(skb)->daddr, &daddr, sizeof(daddr)) ||

net/netfilter/Kconfig

@@ -450,6 +450,15 @@ config NFT_LIMIT
 	depends on NF_TABLES
 	tristate "Netfilter nf_tables limit module"
 
+config NFT_COMPAT
+	depends on NF_TABLES
+	depends on NETFILTER_XTABLES
+	tristate "Netfilter x_tables over nf_tables module"
+	help
+	  This is required if you intend to use any of existing
+	  x_tables match/target extensions over the nf_tables
+	  framework.
+
 config NETFILTER_XTABLES
 	tristate "Netfilter Xtables support (required for ip_tables)"
 	default m if NETFILTER_ADVANCED=n

net/netfilter/Makefile

@@ -70,6 +70,7 @@ nf_tables-objs += nft_immediate.o nft_cmp.o nft_lookup.o
 nf_tables-objs += nft_bitwise.o nft_byteorder.o nft_payload.o
 
 obj-$(CONFIG_NF_TABLES)		+= nf_tables.o
+obj-$(CONFIG_NFT_COMPAT)	+= nft_compat.o
 obj-$(CONFIG_NFT_EXTHDR)	+= nft_exthdr.o
 obj-$(CONFIG_NFT_META)		+= nft_meta.o
 obj-$(CONFIG_NFT_CT)		+= nft_ct.o

net/netfilter/nf_tables_core.c

@@ -60,27 +60,34 @@ static bool nft_payload_fast_eval(const struct nft_expr *expr,
 	return true;
 }
 
-unsigned int nft_do_chain(const struct nf_hook_ops *ops,
-			  struct sk_buff *skb,
-			  const struct net_device *in,
-			  const struct net_device *out,
-			  int (*okfn)(struct sk_buff *))
+struct nft_jumpstack {
+	const struct nft_chain	*chain;
+	const struct nft_rule	*rule;
+};
+
+static inline void
+nft_chain_stats(const struct nft_chain *this, const struct nft_pktinfo *pkt,
+		struct nft_jumpstack *jumpstack, unsigned int stackptr)
+{
+	struct nft_stats __percpu *stats;
+	const struct nft_chain *chain = stackptr ? jumpstack[0].chain : this;
+
+	rcu_read_lock_bh();
+	stats = rcu_dereference(nft_base_chain(chain)->stats);
+	__this_cpu_inc(stats->pkts);
+	__this_cpu_add(stats->bytes, pkt->skb->len);
+	rcu_read_unlock_bh();
+}
+
+unsigned int
+nft_do_chain_pktinfo(struct nft_pktinfo *pkt, const struct nf_hook_ops *ops)
 {
 	const struct nft_chain *chain = ops->priv;
 	const struct nft_rule *rule;
 	const struct nft_expr *expr, *last;
 	struct nft_data data[NFT_REG_MAX + 1];
-	const struct nft_pktinfo pkt = {
-		.skb		= skb,
-		.in		= in,
-		.out		= out,
-		.hooknum	= ops->hooknum,
-	};
 	unsigned int stackptr = 0;
-	struct {
-		const struct nft_chain	*chain;
-		const struct nft_rule	*rule;
-	} jumpstack[NFT_JUMP_STACK_SIZE];
+	struct nft_jumpstack jumpstack[NFT_JUMP_STACK_SIZE];
 
 do_chain:
 	rule = list_entry(&chain->rules, struct nft_rule, list);
@@ -91,8 +98,8 @@ unsigned int nft_do_chain(const struct nf_hook_ops *ops,
 			if (expr->ops == &nft_cmp_fast_ops)
 				nft_cmp_fast_eval(expr, data);
 			else if (expr->ops != &nft_payload_fast_ops ||
-				 !nft_payload_fast_eval(expr, data, &pkt))
-				expr->ops->eval(expr, data, &pkt);
+				 !nft_payload_fast_eval(expr, data, pkt))
+				expr->ops->eval(expr, data, pkt);
 
 			if (data[NFT_REG_VERDICT].verdict != NFT_CONTINUE)
 				break;
@@ -135,10 +142,11 @@ unsigned int nft_do_chain(const struct nf_hook_ops *ops,
 		rule  = jumpstack[stackptr].rule;
 		goto next_rule;
 	}
+	nft_chain_stats(chain, pkt, jumpstack, stackptr);
 
-	return NF_ACCEPT;
+	return nft_base_chain(chain)->policy;
 }
-EXPORT_SYMBOL_GPL(nft_do_chain);
+EXPORT_SYMBOL_GPL(nft_do_chain_pktinfo);
 
 int __init nf_tables_core_module_init(void)
 {

net/netfilter/nft_cmp.c

@@ -162,7 +162,8 @@ const struct nft_expr_ops nft_cmp_fast_ops = {
 	.dump		= nft_cmp_fast_dump,
 };
 
-static const struct nft_expr_ops *nft_cmp_select_ops(const struct nlattr * const tb[])
+static const struct nft_expr_ops *
+nft_cmp_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[])
 {
 	struct nft_data_desc desc;
 	struct nft_data data;

net/netfilter/nft_immediate.c

@@ -90,14 +90,16 @@ static int nft_immediate_dump(struct sk_buff *skb, const struct nft_expr *expr)
 	return -1;
 }
 
-static const struct nft_data *nft_immediate_get_verdict(const struct nft_expr *expr)
+static int nft_immediate_validate(const struct nft_ctx *ctx,
+				  const struct nft_expr *expr,
+				  const struct nft_data **data)
 {
 	const struct nft_immediate_expr *priv = nft_expr_priv(expr);
 
 	if (priv->dreg == NFT_REG_VERDICT)
-		return &priv->data;
-	else
-		return NULL;
+		*data = &priv->data;
+
+	return 0;
 }
 
 static struct nft_expr_type nft_imm_type;
@@ -108,7 +110,7 @@ static const struct nft_expr_ops nft_imm_ops = {
 	.init		= nft_immediate_init,
 	.destroy	= nft_immediate_destroy,
 	.dump		= nft_immediate_dump,
-	.get_verdict	= nft_immediate_get_verdict,
+	.validate	= nft_immediate_validate,
 };
 
 static struct nft_expr_type nft_imm_type __read_mostly = {

net/netfilter/nft_payload.c

@@ -107,7 +107,9 @@ const struct nft_expr_ops nft_payload_fast_ops = {
 	.dump		= nft_payload_dump,
 };
 
-static const struct nft_expr_ops *nft_payload_select_ops(const struct nlattr * const tb[])
+static const struct nft_expr_ops *
+nft_payload_select_ops(const struct nft_ctx *ctx,
+		       const struct nlattr * const tb[])
 {
 	enum nft_payload_bases base;
 	unsigned int offset, len;