netfilter: nf_tables: Add support for IPv6 NAT

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>

9 files changed, 457 insertions, 162 deletions

diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index a9c4bce1988f..7d4a1992f89c 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -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)
diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig
index ae65fe98bfbe..1f37ef67f1ac 100644
--- a/net/ipv4/netfilter/Kconfig
+++ b/net/ipv4/netfilter/Kconfig
@@ -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
diff --git a/net/ipv4/netfilter/nft_chain_nat_ipv4.c b/net/ipv4/netfilter/nft_chain_nat_ipv4.c
index e09c201adf84..cf2c792cd971 100644
--- a/net/ipv4/netfilter/nft_chain_nat_ipv4.c
+++ b/net/ipv4/netfilter/nft_chain_nat_ipv4.c
@@ -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
@@ -14,10 +15,8 @@
 #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>
@@ -27,147 +26,6 @@
 #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;