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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
* Copyright (c) 2012 Pablo Neira Ayuso <pablo@netfilter.org>
* Copyright (c) 2012 Intel Corporation
*/
#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_tables.h>
#include <net/ip.h>
struct nft_nat {
u8 sreg_addr_min;
u8 sreg_addr_max;
u8 sreg_proto_min;
u8 sreg_proto_max;
enum nf_nat_manip_type type:8;
u8 family;
u16 flags;
};
static void nft_nat_setup_addr(struct nf_nat_range2 *range,
const struct nft_regs *regs,
const struct nft_nat *priv)
{
switch (priv->family) {
case AF_INET:
range->min_addr.ip = (__force __be32)
regs->data[priv->sreg_addr_min];
range->max_addr.ip = (__force __be32)
regs->data[priv->sreg_addr_max];
break;
case AF_INET6:
memcpy(range->min_addr.ip6, ®s->data[priv->sreg_addr_min],
sizeof(range->min_addr.ip6));
memcpy(range->max_addr.ip6, ®s->data[priv->sreg_addr_max],
sizeof(range->max_addr.ip6));
break;
}
}
static void nft_nat_setup_proto(struct nf_nat_range2 *range,
const struct nft_regs *regs,
const struct nft_nat *priv)
{
range->min_proto.all = (__force __be16)
nft_reg_load16(®s->data[priv->sreg_proto_min]);
range->max_proto.all = (__force __be16)
nft_reg_load16(®s->data[priv->sreg_proto_max]);
}
static void nft_nat_setup_netmap(struct nf_nat_range2 *range,
const struct nft_pktinfo *pkt,
const struct nft_nat *priv)
{
struct sk_buff *skb = pkt->skb;
union nf_inet_addr new_addr;
__be32 netmask;
int i, len = 0;
switch (priv->type) {
case NFT_NAT_SNAT:
if (nft_pf(pkt) == NFPROTO_IPV4) {
new_addr.ip = ip_hdr(skb)->saddr;
len = sizeof(struct in_addr);
} else {
new_addr.in6 = ipv6_hdr(skb)->saddr;
len = sizeof(struct in6_addr);
}
break;
case NFT_NAT_DNAT:
if (nft_pf(pkt) == NFPROTO_IPV4) {
new_addr.ip = ip_hdr(skb)->daddr;
len = sizeof(struct in_addr);
} else {
new_addr.in6 = ipv6_hdr(skb)->daddr;
len = sizeof(struct in6_addr);
}
break;
}
for (i = 0; i < len / sizeof(__be32); i++) {
netmask = ~(range->min_addr.ip6[i] ^ range->max_addr.ip6[i]);
new_addr.ip6[i] &= ~netmask;
new_addr.ip6[i] |= range->min_addr.ip6[i] & netmask;
}
range->min_addr = new_addr;
range->max_addr = new_addr;
}
static void nft_nat_eval(const struct nft_expr *expr,
struct nft_regs *regs,
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_range2 range;
memset(&range, 0, sizeof(range));
if (priv->sreg_addr_min) {
nft_nat_setup_addr(&range, regs, priv);
if (priv->flags & NF_NAT_RANGE_NETMAP)
nft_nat_setup_netmap(&range, pkt, priv);
}
if (priv->sreg_proto_min)
nft_nat_setup_proto(&range, regs, priv);
range.flags = priv->flags;
regs->verdict.code = 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 },
[NFTA_NAT_FLAGS] = { .type = NLA_U32 },
};
static int nft_nat_validate(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nft_data **data)
{
struct nft_nat *priv = nft_expr_priv(expr);
int err;
err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT);
if (err < 0)
return err;
switch (priv->type) {
case NFT_NAT_SNAT:
err = nft_chain_validate_hooks(ctx->chain,
(1 << NF_INET_POST_ROUTING) |
(1 << NF_INET_LOCAL_IN));
break;
case NFT_NAT_DNAT:
err = nft_chain_validate_hooks(ctx->chain,
(1 << NF_INET_PRE_ROUTING) |
(1 << NF_INET_LOCAL_OUT));
break;
}
return err;
}
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);
unsigned int alen, plen;
u32 family;
int err;
if (tb[NFTA_NAT_TYPE] == NULL ||
(tb[NFTA_NAT_REG_ADDR_MIN] == NULL &&
tb[NFTA_NAT_REG_PROTO_MIN] == 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 -EOPNOTSUPP;
}
if (tb[NFTA_NAT_FAMILY] == NULL)
return -EINVAL;
family = ntohl(nla_get_be32(tb[NFTA_NAT_FAMILY]));
if (ctx->family != NFPROTO_INET && ctx->family != family)
return -EOPNOTSUPP;
switch (family) {
case NFPROTO_IPV4:
alen = sizeof_field(struct nf_nat_range, min_addr.ip);
break;
case NFPROTO_IPV6:
alen = sizeof_field(struct nf_nat_range, min_addr.ip6);
break;
default:
if (tb[NFTA_NAT_REG_ADDR_MIN])
return -EAFNOSUPPORT;
break;
}
priv->family = family;
if (tb[NFTA_NAT_REG_ADDR_MIN]) {
err = nft_parse_register_load(tb[NFTA_NAT_REG_ADDR_MIN],
&priv->sreg_addr_min, alen);
if (err < 0)
return err;
if (tb[NFTA_NAT_REG_ADDR_MAX]) {
err = nft_parse_register_load(tb[NFTA_NAT_REG_ADDR_MAX],
&priv->sreg_addr_max,
alen);
if (err < 0)
return err;
} else {
priv->sreg_addr_max = priv->sreg_addr_min;
}
priv->flags |= NF_NAT_RANGE_MAP_IPS;
}
plen = sizeof_field(struct nf_nat_range, min_proto.all);
if (tb[NFTA_NAT_REG_PROTO_MIN]) {
err = nft_parse_register_load(tb[NFTA_NAT_REG_PROTO_MIN],
&priv->sreg_proto_min, plen);
if (err < 0)
return err;
if (tb[NFTA_NAT_REG_PROTO_MAX]) {
err = nft_parse_register_load(tb[NFTA_NAT_REG_PROTO_MAX],
&priv->sreg_proto_max,
plen);
if (err < 0)
return err;
} else {
priv->sreg_proto_max = priv->sreg_proto_min;
}
priv->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
}
if (tb[NFTA_NAT_FLAGS]) {
priv->flags |= ntohl(nla_get_be32(tb[NFTA_NAT_FLAGS]));
if (priv->flags & ~NF_NAT_RANGE_MASK)
return -EOPNOTSUPP;
}
return nf_ct_netns_get(ctx->net, family);
}
static int nft_nat_dump(struct sk_buff *skb,
const struct nft_expr *expr, bool reset)
{
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 (priv->sreg_addr_min) {
if (nft_dump_register(skb, NFTA_NAT_REG_ADDR_MIN,
priv->sreg_addr_min) ||
nft_dump_register(skb, NFTA_NAT_REG_ADDR_MAX,
priv->sreg_addr_max))
goto nla_put_failure;
}
if (priv->sreg_proto_min) {
if (nft_dump_register(skb, NFTA_NAT_REG_PROTO_MIN,
priv->sreg_proto_min) ||
nft_dump_register(skb, NFTA_NAT_REG_PROTO_MAX,
priv->sreg_proto_max))
goto nla_put_failure;
}
if (priv->flags != 0) {
if (nla_put_be32(skb, NFTA_NAT_FLAGS, htonl(priv->flags)))
goto nla_put_failure;
}
return 0;
nla_put_failure:
return -1;
}
static void
nft_nat_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
{
const struct nft_nat *priv = nft_expr_priv(expr);
nf_ct_netns_put(ctx->net, priv->family);
}
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,
.destroy = nft_nat_destroy,
.dump = nft_nat_dump,
.validate = nft_nat_validate,
.reduce = NFT_REDUCE_READONLY,
};
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,
};
#ifdef CONFIG_NF_TABLES_INET
static void nft_nat_inet_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
const struct nft_nat *priv = nft_expr_priv(expr);
if (priv->family == nft_pf(pkt) ||
priv->family == NFPROTO_INET)
nft_nat_eval(expr, regs, pkt);
}
static const struct nft_expr_ops nft_nat_inet_ops = {
.type = &nft_nat_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_nat)),
.eval = nft_nat_inet_eval,
.init = nft_nat_init,
.destroy = nft_nat_destroy,
.dump = nft_nat_dump,
.validate = nft_nat_validate,
.reduce = NFT_REDUCE_READONLY,
};
static struct nft_expr_type nft_inet_nat_type __read_mostly = {
.name = "nat",
.family = NFPROTO_INET,
.ops = &nft_nat_inet_ops,
.policy = nft_nat_policy,
.maxattr = NFTA_NAT_MAX,
.owner = THIS_MODULE,
};
static int nft_nat_inet_module_init(void)
{
return nft_register_expr(&nft_inet_nat_type);
}
static void nft_nat_inet_module_exit(void)
{
nft_unregister_expr(&nft_inet_nat_type);
}
#else
static int nft_nat_inet_module_init(void) { return 0; }
static void nft_nat_inet_module_exit(void) { }
#endif
static int __init nft_nat_module_init(void)
{
int ret = nft_nat_inet_module_init();
if (ret)
return ret;
ret = nft_register_expr(&nft_nat_type);
if (ret)
nft_nat_inet_module_exit();
return ret;
}
static void __exit nft_nat_module_exit(void)
{
nft_nat_inet_module_exit();
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");
MODULE_DESCRIPTION("Network Address Translation support");
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