netfilter: nf_tables: Add support for IPv6 NAT
authorTomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
Thu, 10 Oct 2013 11:39:19 +0000 (13:39 +0200)
committerPablo Neira Ayuso <pablo@netfilter.org>
Mon, 14 Oct 2013 16:00:58 +0000 (18:00 +0200)
This patch generalizes the NAT expression to support both IPv4 and IPv6
using the existing IPv4/IPv6 NAT infrastructure. This also adds the
NAT chain type for IPv6.

This patch collapses the following patches that were posted to the
netfilter-devel mailing list, from Tomasz:

* nf_tables: Change NFTA_NAT_ attributes to better semantic significance
* nf_tables: Split IPv4 NAT into NAT expression and IPv4 NAT chain
* nf_tables: Add support for IPv6 NAT expression
* nf_tables: Add support for IPv6 NAT chain
* nf_tables: Fix up build issue on IPv6 NAT support

And, from Pablo Neira Ayuso:

* fix missing dependencies in nft_chain_nat

Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
include/uapi/linux/netfilter/nf_tables.h
net/ipv4/netfilter/Kconfig
net/ipv4/netfilter/nft_chain_nat_ipv4.c
net/ipv6/netfilter/Kconfig
net/ipv6/netfilter/Makefile
net/ipv6/netfilter/nft_chain_nat_ipv6.c [new file with mode: 0644]
net/netfilter/Kconfig
net/netfilter/Makefile
net/netfilter/nft_nat.c [new file with mode: 0644]

index a9c4bce..7d4a199 100644 (file)
@@ -695,18 +695,20 @@ enum nft_nat_types {
  * enum nft_nat_attributes - nf_tables nat expression netlink attributes
  *
  * @NFTA_NAT_TYPE: NAT type (NLA_U32: nft_nat_types)
- * @NFTA_NAT_ADDR_MIN: source register of address range start (NLA_U32: nft_registers)
- * @NFTA_NAT_ADDR_MAX: source register of address range end (NLA_U32: nft_registers)
- * @NFTA_NAT_PROTO_MIN: source register of proto range start (NLA_U32: nft_registers)
- * @NFTA_NAT_PROTO_MAX: source register of proto range end (NLA_U32: nft_registers)
+ * @NFTA_NAT_FAMILY: NAT family (NLA_U32)
+ * @NFTA_NAT_REG_ADDR_MIN: source register of address range start (NLA_U32: nft_registers)
+ * @NFTA_NAT_REG_ADDR_MAX: source register of address range end (NLA_U32: nft_registers)
+ * @NFTA_NAT_REG_PROTO_MIN: source register of proto range start (NLA_U32: nft_registers)
+ * @NFTA_NAT_REG_PROTO_MAX: source register of proto range end (NLA_U32: nft_registers)
  */
 enum nft_nat_attributes {
        NFTA_NAT_UNSPEC,
        NFTA_NAT_TYPE,
-       NFTA_NAT_ADDR_MIN,
-       NFTA_NAT_ADDR_MAX,
-       NFTA_NAT_PROTO_MIN,
-       NFTA_NAT_PROTO_MAX,
+       NFTA_NAT_FAMILY,
+       NFTA_NAT_REG_ADDR_MIN,
+       NFTA_NAT_REG_ADDR_MAX,
+       NFTA_NAT_REG_PROTO_MIN,
+       NFTA_NAT_REG_PROTO_MAX,
        __NFTA_NAT_MAX
 };
 #define NFTA_NAT_MAX           (__NFTA_NAT_MAX - 1)
index ae65fe9..1f37ef6 100644 (file)
@@ -50,6 +50,7 @@ config NFT_CHAIN_ROUTE_IPV4
 
 config NFT_CHAIN_NAT_IPV4
        depends on NF_TABLES_IPV4
+       depends on NF_NAT_IPV4 && NFT_NAT
        tristate "IPv4 nf_tables nat chain support"
 
 config IP_NF_IPTABLES
index e09c201..cf2c792 100644 (file)
@@ -1,6 +1,7 @@
 /*
  * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
  * Copyright (c) 2012 Pablo Neira Ayuso <pablo@netfilter.org>
+ * Copyright (c) 2012 Intel Corporation
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
 #include <linux/list.h>
 #include <linux/skbuff.h>
 #include <linux/ip.h>
-#include <linux/netlink.h>
 #include <linux/netfilter.h>
 #include <linux/netfilter_ipv4.h>
-#include <linux/netfilter/nfnetlink.h>
 #include <linux/netfilter/nf_tables.h>
 #include <net/netfilter/nf_conntrack.h>
 #include <net/netfilter/nf_nat.h>
 #include <net/netfilter/nf_nat_l3proto.h>
 #include <net/ip.h>
 
-struct nft_nat {
-       enum nft_registers      sreg_addr_min:8;
-       enum nft_registers      sreg_addr_max:8;
-       enum nft_registers      sreg_proto_min:8;
-       enum nft_registers      sreg_proto_max:8;
-       enum nf_nat_manip_type  type;
-};
-
-static void nft_nat_eval(const struct nft_expr *expr,
-                        struct nft_data data[NFT_REG_MAX + 1],
-                        const struct nft_pktinfo *pkt)
-{
-       const struct nft_nat *priv = nft_expr_priv(expr);
-       enum ip_conntrack_info ctinfo;
-       struct nf_conn *ct = nf_ct_get(pkt->skb, &ctinfo);
-       struct nf_nat_range range;
-
-       memset(&range, 0, sizeof(range));
-       if (priv->sreg_addr_min) {
-               range.min_addr.ip = data[priv->sreg_addr_min].data[0];
-               range.max_addr.ip = data[priv->sreg_addr_max].data[0];
-               range.flags |= NF_NAT_RANGE_MAP_IPS;
-       }
-
-       if (priv->sreg_proto_min) {
-               range.min_proto.all = data[priv->sreg_proto_min].data[0];
-               range.max_proto.all = data[priv->sreg_proto_max].data[0];
-               range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
-       }
-
-       data[NFT_REG_VERDICT].verdict =
-               nf_nat_setup_info(ct, &range, priv->type);
-}
-
-static const struct nla_policy nft_nat_policy[NFTA_NAT_MAX + 1] = {
-       [NFTA_NAT_ADDR_MIN]     = { .type = NLA_U32 },
-       [NFTA_NAT_ADDR_MAX]     = { .type = NLA_U32 },
-       [NFTA_NAT_PROTO_MIN]    = { .type = NLA_U32 },
-       [NFTA_NAT_PROTO_MAX]    = { .type = NLA_U32 },
-       [NFTA_NAT_TYPE]         = { .type = NLA_U32 },
-};
-
-static int nft_nat_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
-                       const struct nlattr * const tb[])
-{
-       struct nft_nat *priv = nft_expr_priv(expr);
-       int err;
-
-       if (tb[NFTA_NAT_TYPE] == NULL)
-               return -EINVAL;
-
-       switch (ntohl(nla_get_be32(tb[NFTA_NAT_TYPE]))) {
-       case NFT_NAT_SNAT:
-               priv->type = NF_NAT_MANIP_SRC;
-               break;
-       case NFT_NAT_DNAT:
-               priv->type = NF_NAT_MANIP_DST;
-               break;
-       default:
-               return -EINVAL;
-       }
-
-       if (tb[NFTA_NAT_ADDR_MIN]) {
-               priv->sreg_addr_min = ntohl(nla_get_be32(tb[NFTA_NAT_ADDR_MIN]));
-               err = nft_validate_input_register(priv->sreg_addr_min);
-               if (err < 0)
-                       return err;
-       }
-
-       if (tb[NFTA_NAT_ADDR_MAX]) {
-               priv->sreg_addr_max = ntohl(nla_get_be32(tb[NFTA_NAT_ADDR_MAX]));
-               err = nft_validate_input_register(priv->sreg_addr_max);
-               if (err < 0)
-                       return err;
-       } else
-               priv->sreg_addr_max = priv->sreg_addr_min;
-
-       if (tb[NFTA_NAT_PROTO_MIN]) {
-               priv->sreg_proto_min = ntohl(nla_get_be32(tb[NFTA_NAT_PROTO_MIN]));
-               err = nft_validate_input_register(priv->sreg_proto_min);
-               if (err < 0)
-                       return err;
-       }
-
-       if (tb[NFTA_NAT_PROTO_MAX]) {
-               priv->sreg_proto_max = ntohl(nla_get_be32(tb[NFTA_NAT_PROTO_MAX]));
-               err = nft_validate_input_register(priv->sreg_proto_max);
-               if (err < 0)
-                       return err;
-       } else
-               priv->sreg_proto_max = priv->sreg_proto_min;
-
-       return 0;
-}
-
-static int nft_nat_dump(struct sk_buff *skb, const struct nft_expr *expr)
-{
-       const struct nft_nat *priv = nft_expr_priv(expr);
-
-       switch (priv->type) {
-       case NF_NAT_MANIP_SRC:
-               if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_SNAT)))
-                       goto nla_put_failure;
-               break;
-       case NF_NAT_MANIP_DST:
-               if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_DNAT)))
-                       goto nla_put_failure;
-               break;
-       }
-
-       if (nla_put_be32(skb, NFTA_NAT_ADDR_MIN, htonl(priv->sreg_addr_min)))
-               goto nla_put_failure;
-       if (nla_put_be32(skb, NFTA_NAT_ADDR_MAX, htonl(priv->sreg_addr_max)))
-               goto nla_put_failure;
-       if (nla_put_be32(skb, NFTA_NAT_PROTO_MIN, htonl(priv->sreg_proto_min)))
-               goto nla_put_failure;
-       if (nla_put_be32(skb, NFTA_NAT_PROTO_MAX, htonl(priv->sreg_proto_max)))
-               goto nla_put_failure;
-       return 0;
-
-nla_put_failure:
-       return -1;
-}
-
-static struct nft_expr_type nft_nat_type;
-static const struct nft_expr_ops nft_nat_ops = {
-       .type           = &nft_nat_type,
-       .size           = NFT_EXPR_SIZE(sizeof(struct nft_nat)),
-       .eval           = nft_nat_eval,
-       .init           = nft_nat_init,
-       .dump           = nft_nat_dump,
-};
-
-static struct nft_expr_type nft_nat_type __read_mostly = {
-       .name           = "nat",
-       .ops            = &nft_nat_ops,
-       .policy         = nft_nat_policy,
-       .maxattr        = NFTA_NAT_MAX,
-       .owner          = THIS_MODULE,
-};
-
 /*
  * NAT chains
  */
@@ -306,7 +164,7 @@ static unsigned int nf_nat_output(const struct nf_hook_ops *ops,
        return ret;
 }
 
-struct nf_chain_type nft_chain_nat_ipv4 = {
+static struct nf_chain_type nft_chain_nat_ipv4 = {
        .family         = NFPROTO_IPV4,
        .name           = "nat",
        .type           = NFT_CHAIN_T_NAT,
@@ -331,20 +189,11 @@ static int __init nft_chain_nat_init(void)
        if (err < 0)
                return err;
 
-       err = nft_register_expr(&nft_nat_type);
-       if (err < 0)
-               goto err;
-
        return 0;
-
-err:
-       nft_unregister_chain_type(&nft_chain_nat_ipv4);
-       return err;
 }
 
 static void __exit nft_chain_nat_exit(void)
 {
-       nft_unregister_expr(&nft_nat_type);
        nft_unregister_chain_type(&nft_chain_nat_ipv4);
 }
 
@@ -354,4 +203,3 @@ module_exit(nft_chain_nat_exit);
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 MODULE_ALIAS_NFT_CHAIN(AF_INET, "nat");
-MODULE_ALIAS_NFT_EXPR("nat");
index 2383306..7702f9e 100644 (file)
@@ -33,6 +33,11 @@ config NFT_CHAIN_ROUTE_IPV6
        depends on NF_TABLES_IPV6
        tristate "IPv6 nf_tables route chain support"
 
+config NFT_CHAIN_NAT_IPV6
+       depends on NF_TABLES_IPV6
+       depends on NF_NAT_IPV6 && NFT_NAT
+       tristate "IPv6 nf_tables nat chain support"
+
 config IP6_NF_IPTABLES
        tristate "IP6 tables support (required for filtering)"
        depends on INET && IPV6
index be4913a..d1b4928 100644 (file)
@@ -26,6 +26,7 @@ obj-$(CONFIG_NF_DEFRAG_IPV6) += nf_defrag_ipv6.o
 # nf_tables
 obj-$(CONFIG_NF_TABLES_IPV6) += nf_tables_ipv6.o
 obj-$(CONFIG_NFT_CHAIN_ROUTE_IPV6) += nft_chain_route_ipv6.o
+obj-$(CONFIG_NFT_CHAIN_NAT_IPV6) += nft_chain_nat_ipv6.o
 
 # matches
 obj-$(CONFIG_IP6_NF_MATCH_AH) += ip6t_ah.o
diff --git a/net/ipv6/netfilter/nft_chain_nat_ipv6.c b/net/ipv6/netfilter/nft_chain_nat_ipv6.c
new file mode 100644 (file)
index 0000000..e86dcd7
--- /dev/null
@@ -0,0 +1,211 @@
+/*
+ * Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
+ * Copyright (c) 2012 Intel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/skbuff.h>
+#include <linux/ip.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter_ipv6.h>
+#include <linux/netfilter/nf_tables.h>
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_nat.h>
+#include <net/netfilter/nf_nat_core.h>
+#include <net/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables_ipv6.h>
+#include <net/netfilter/nf_nat_l3proto.h>
+#include <net/ipv6.h>
+
+/*
+ * IPv6 NAT chains
+ */
+
+static unsigned int nf_nat_ipv6_fn(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 *))
+{
+       enum ip_conntrack_info ctinfo;
+       struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+       struct nf_conn_nat *nat;
+       enum nf_nat_manip_type maniptype = HOOK2MANIP(ops->hooknum);
+       __be16 frag_off;
+       int hdrlen;
+       u8 nexthdr;
+       struct nft_pktinfo pkt;
+       unsigned int ret;
+
+       if (ct == NULL || nf_ct_is_untracked(ct))
+               return NF_ACCEPT;
+
+       nat = nfct_nat(ct);
+       if (nat == NULL) {
+               /* Conntrack module was loaded late, can't add extension. */
+               if (nf_ct_is_confirmed(ct))
+                       return NF_ACCEPT;
+               nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC);
+               if (nat == NULL)
+                       return NF_ACCEPT;
+       }
+
+       switch (ctinfo) {
+       case IP_CT_RELATED:
+       case IP_CT_RELATED + IP_CT_IS_REPLY:
+               nexthdr = ipv6_hdr(skb)->nexthdr;
+               hdrlen = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr),
+                                         &nexthdr, &frag_off);
+
+               if (hdrlen >= 0 && nexthdr == IPPROTO_ICMPV6) {
+                       if (!nf_nat_icmpv6_reply_translation(skb, ct, ctinfo,
+                                                          ops->hooknum,
+                                                          hdrlen))
+                               return NF_DROP;
+                       else
+                               return NF_ACCEPT;
+               }
+               /* Fall through */
+       case IP_CT_NEW:
+               if (nf_nat_initialized(ct, maniptype))
+                       break;
+
+               nft_set_pktinfo_ipv6(&pkt, ops, skb, in, out);
+
+               ret = nft_do_chain_pktinfo(&pkt, ops);
+               if (ret != NF_ACCEPT)
+                       return ret;
+               if (!nf_nat_initialized(ct, maniptype)) {
+                       ret = nf_nat_alloc_null_binding(ct, ops->hooknum);
+                       if (ret != NF_ACCEPT)
+                               return ret;
+               }
+       default:
+               break;
+       }
+
+       return nf_nat_packet(ct, ctinfo, ops->hooknum, skb);
+}
+
+static unsigned int nf_nat_ipv6_prerouting(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 in6_addr daddr = ipv6_hdr(skb)->daddr;
+       unsigned int ret;
+
+       ret = nf_nat_ipv6_fn(ops, skb, in, out, okfn);
+       if (ret != NF_DROP && ret != NF_STOLEN &&
+           ipv6_addr_cmp(&daddr, &ipv6_hdr(skb)->daddr))
+               skb_dst_drop(skb);
+
+       return ret;
+}
+
+static unsigned int nf_nat_ipv6_postrouting(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 *))
+{
+       enum ip_conntrack_info ctinfo __maybe_unused;
+       const struct nf_conn *ct __maybe_unused;
+       unsigned int ret;
+
+       ret = nf_nat_ipv6_fn(ops, skb, in, out, okfn);
+#ifdef CONFIG_XFRM
+       if (ret != NF_DROP && ret != NF_STOLEN &&
+           !(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
+           (ct = nf_ct_get(skb, &ctinfo)) != NULL) {
+               enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+
+               if (!nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3,
+                                     &ct->tuplehash[!dir].tuple.dst.u3) ||
+                   (ct->tuplehash[dir].tuple.src.u.all !=
+                    ct->tuplehash[!dir].tuple.dst.u.all))
+                       if (nf_xfrm_me_harder(skb, AF_INET6) < 0)
+                               ret = NF_DROP;
+       }
+#endif
+       return ret;
+}
+
+static unsigned int nf_nat_ipv6_output(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 *))
+{
+       enum ip_conntrack_info ctinfo;
+       const struct nf_conn *ct;
+       unsigned int ret;
+
+       ret = nf_nat_ipv6_fn(ops, skb, in, out, okfn);
+       if (ret != NF_DROP && ret != NF_STOLEN &&
+           (ct = nf_ct_get(skb, &ctinfo)) != NULL) {
+               enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+
+               if (!nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.dst.u3,
+                                     &ct->tuplehash[!dir].tuple.src.u3)) {
+                       if (ip6_route_me_harder(skb))
+                               ret = NF_DROP;
+               }
+#ifdef CONFIG_XFRM
+               else if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
+                        ct->tuplehash[dir].tuple.dst.u.all !=
+                        ct->tuplehash[!dir].tuple.src.u.all)
+                       if (nf_xfrm_me_harder(skb, AF_INET6))
+                               ret = NF_DROP;
+#endif
+       }
+       return ret;
+}
+
+static struct nf_chain_type nft_chain_nat_ipv6 = {
+       .family         = NFPROTO_IPV6,
+       .name           = "nat",
+       .type           = NFT_CHAIN_T_NAT,
+       .hook_mask      = (1 << NF_INET_PRE_ROUTING) |
+                         (1 << NF_INET_POST_ROUTING) |
+                         (1 << NF_INET_LOCAL_OUT) |
+                         (1 << NF_INET_LOCAL_IN),
+       .fn             = {
+               [NF_INET_PRE_ROUTING]   = nf_nat_ipv6_prerouting,
+               [NF_INET_POST_ROUTING]  = nf_nat_ipv6_postrouting,
+               [NF_INET_LOCAL_OUT]     = nf_nat_ipv6_output,
+               [NF_INET_LOCAL_IN]      = nf_nat_ipv6_fn,
+       },
+       .me             = THIS_MODULE,
+};
+
+static int __init nft_chain_nat_ipv6_init(void)
+{
+       int err;
+
+       err = nft_register_chain_type(&nft_chain_nat_ipv6);
+       if (err < 0)
+               return err;
+
+       return 0;
+}
+
+static void __exit nft_chain_nat_ipv6_exit(void)
+{
+       nft_unregister_chain_type(&nft_chain_nat_ipv6);
+}
+
+module_init(nft_chain_nat_ipv6_init);
+module_exit(nft_chain_nat_ipv6_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>");
+MODULE_ALIAS_NFT_CHAIN(AF_INET6, "nat");
index 49e3627..48acec1 100644 (file)
@@ -450,6 +450,12 @@ config NFT_LIMIT
        depends on NF_TABLES
        tristate "Netfilter nf_tables limit module"
 
+config NFT_NAT
+       depends on NF_TABLES
+       depends on NF_CONNTRACK
+       depends on NF_NAT
+       tristate "Netfilter nf_tables nat module"
+
 config NFT_COMPAT
        depends on NF_TABLES
        depends on NETFILTER_XTABLES
index a678145..394483b 100644 (file)
@@ -75,6 +75,7 @@ obj-$(CONFIG_NFT_EXTHDR)      += nft_exthdr.o
 obj-$(CONFIG_NFT_META)         += nft_meta.o
 obj-$(CONFIG_NFT_CT)           += nft_ct.o
 obj-$(CONFIG_NFT_LIMIT)                += nft_limit.o
+obj-$(CONFIG_NFT_NAT)          += nft_nat.o
 #nf_tables-objs                        += nft_meta_target.o
 obj-$(CONFIG_NFT_RBTREE)       += nft_rbtree.o
 obj-$(CONFIG_NFT_HASH)         += nft_hash.o
diff --git a/net/netfilter/nft_nat.c b/net/netfilter/nft_nat.c
new file mode 100644 (file)
index 0000000..b0b87b2
--- /dev/null
@@ -0,0 +1,220 @@
+/*
+ * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
+ * Copyright (c) 2012 Pablo Neira Ayuso <pablo@netfilter.org>
+ * Copyright (c) 2012 Intel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/skbuff.h>
+#include <linux/ip.h>
+#include <linux/string.h>
+#include <linux/netlink.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter_ipv4.h>
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netfilter/nf_tables.h>
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_nat.h>
+#include <net/netfilter/nf_nat_core.h>
+#include <net/netfilter/nf_tables.h>
+#include <net/netfilter/nf_nat_l3proto.h>
+#include <net/ip.h>
+
+struct nft_nat {
+       enum nft_registers      sreg_addr_min:8;
+       enum nft_registers      sreg_addr_max:8;
+       enum nft_registers      sreg_proto_min:8;
+       enum nft_registers      sreg_proto_max:8;
+       int                     family;
+       enum nf_nat_manip_type  type;
+};
+
+static void nft_nat_eval(const struct nft_expr *expr,
+                        struct nft_data data[NFT_REG_MAX + 1],
+                        const struct nft_pktinfo *pkt)
+{
+       const struct nft_nat *priv = nft_expr_priv(expr);
+       enum ip_conntrack_info ctinfo;
+       struct nf_conn *ct = nf_ct_get(pkt->skb, &ctinfo);
+       struct nf_nat_range range;
+
+       memset(&range, 0, sizeof(range));
+       if (priv->sreg_addr_min) {
+               if (priv->family == AF_INET) {
+                       range.min_addr.ip = data[priv->sreg_addr_min].data[0];
+                       range.max_addr.ip = data[priv->sreg_addr_max].data[0];
+
+               } else {
+                       memcpy(range.min_addr.ip6,
+                              data[priv->sreg_addr_min].data,
+                              sizeof(struct nft_data));
+                       memcpy(range.max_addr.ip6,
+                              data[priv->sreg_addr_max].data,
+                              sizeof(struct nft_data));
+               }
+               range.flags |= NF_NAT_RANGE_MAP_IPS;
+       }
+
+       if (priv->sreg_proto_min) {
+               range.min_proto.all = data[priv->sreg_proto_min].data[0];
+               range.max_proto.all = data[priv->sreg_proto_max].data[0];
+               range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
+       }
+
+       data[NFT_REG_VERDICT].verdict =
+               nf_nat_setup_info(ct, &range, priv->type);
+}
+
+static const struct nla_policy nft_nat_policy[NFTA_NAT_MAX + 1] = {
+       [NFTA_NAT_TYPE]          = { .type = NLA_U32 },
+       [NFTA_NAT_FAMILY]        = { .type = NLA_U32 },
+       [NFTA_NAT_REG_ADDR_MIN]  = { .type = NLA_U32 },
+       [NFTA_NAT_REG_ADDR_MAX]  = { .type = NLA_U32 },
+       [NFTA_NAT_REG_PROTO_MIN] = { .type = NLA_U32 },
+       [NFTA_NAT_REG_PROTO_MAX] = { .type = NLA_U32 },
+};
+
+static int nft_nat_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
+                       const struct nlattr * const tb[])
+{
+       struct nft_nat *priv = nft_expr_priv(expr);
+       int err;
+
+       if (tb[NFTA_NAT_TYPE] == NULL)
+               return -EINVAL;
+
+       switch (ntohl(nla_get_be32(tb[NFTA_NAT_TYPE]))) {
+       case NFT_NAT_SNAT:
+               priv->type = NF_NAT_MANIP_SRC;
+               break;
+       case NFT_NAT_DNAT:
+               priv->type = NF_NAT_MANIP_DST;
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       if (tb[NFTA_NAT_FAMILY] == NULL)
+               return -EINVAL;
+
+       priv->family = ntohl(nla_get_be32(tb[NFTA_NAT_FAMILY]));
+       if (priv->family != AF_INET && priv->family != AF_INET6)
+               return -EINVAL;
+
+       if (tb[NFTA_NAT_REG_ADDR_MIN]) {
+               priv->sreg_addr_min = ntohl(nla_get_be32(
+                                               tb[NFTA_NAT_REG_ADDR_MIN]));
+               err = nft_validate_input_register(priv->sreg_addr_min);
+               if (err < 0)
+                       return err;
+       }
+
+       if (tb[NFTA_NAT_REG_ADDR_MAX]) {
+               priv->sreg_addr_max = ntohl(nla_get_be32(
+                                               tb[NFTA_NAT_REG_ADDR_MAX]));
+               err = nft_validate_input_register(priv->sreg_addr_max);
+               if (err < 0)
+                       return err;
+       } else
+               priv->sreg_addr_max = priv->sreg_addr_min;
+
+       if (tb[NFTA_NAT_REG_PROTO_MIN]) {
+               priv->sreg_proto_min = ntohl(nla_get_be32(
+                                               tb[NFTA_NAT_REG_PROTO_MIN]));
+               err = nft_validate_input_register(priv->sreg_proto_min);
+               if (err < 0)
+                       return err;
+       }
+
+       if (tb[NFTA_NAT_REG_PROTO_MAX]) {
+               priv->sreg_proto_max = ntohl(nla_get_be32(
+                                               tb[NFTA_NAT_REG_PROTO_MAX]));
+               err = nft_validate_input_register(priv->sreg_proto_max);
+               if (err < 0)
+                       return err;
+       } else
+               priv->sreg_proto_max = priv->sreg_proto_min;
+
+       return 0;
+}
+
+static int nft_nat_dump(struct sk_buff *skb, const struct nft_expr *expr)
+{
+       const struct nft_nat *priv = nft_expr_priv(expr);
+
+       switch (priv->type) {
+       case NF_NAT_MANIP_SRC:
+               if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_SNAT)))
+                       goto nla_put_failure;
+               break;
+       case NF_NAT_MANIP_DST:
+               if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_DNAT)))
+                       goto nla_put_failure;
+               break;
+       }
+
+       if (nla_put_be32(skb, NFTA_NAT_FAMILY, htonl(priv->family)))
+               goto nla_put_failure;
+       if (nla_put_be32(skb,
+                        NFTA_NAT_REG_ADDR_MIN, htonl(priv->sreg_addr_min)))
+               goto nla_put_failure;
+       if (nla_put_be32(skb,
+                        NFTA_NAT_REG_ADDR_MAX, htonl(priv->sreg_addr_max)))
+               goto nla_put_failure;
+       if (nla_put_be32(skb,
+                        NFTA_NAT_REG_PROTO_MIN, htonl(priv->sreg_proto_min)))
+               goto nla_put_failure;
+       if (nla_put_be32(skb,
+                        NFTA_NAT_REG_PROTO_MAX, htonl(priv->sreg_proto_max)))
+               goto nla_put_failure;
+       return 0;
+
+nla_put_failure:
+       return -1;
+}
+
+static struct nft_expr_type nft_nat_type;
+static const struct nft_expr_ops nft_nat_ops = {
+       .type           = &nft_nat_type,
+       .size           = NFT_EXPR_SIZE(sizeof(struct nft_nat)),
+       .eval           = nft_nat_eval,
+       .init           = nft_nat_init,
+       .dump           = nft_nat_dump,
+};
+
+static struct nft_expr_type nft_nat_type __read_mostly = {
+       .name           = "nat",
+       .ops            = &nft_nat_ops,
+       .policy         = nft_nat_policy,
+       .maxattr        = NFTA_NAT_MAX,
+       .owner          = THIS_MODULE,
+};
+
+static int __init nft_nat_module_init(void)
+{
+       int err;
+
+       err = nft_register_expr(&nft_nat_type);
+       if (err < 0)
+               return err;
+
+       return 0;
+}
+
+static void __exit nft_nat_module_exit(void)
+{
+       nft_unregister_expr(&nft_nat_type);
+}
+
+module_init(nft_nat_module_init);
+module_exit(nft_nat_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>");
+MODULE_ALIAS_NFT_EXPR("nat");