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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2014 Arturo Borrero Gonzalez <arturo@debian.org>
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/netlink.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <net/netfilter/nf_tables.h>
#include <net/netfilter/nf_nat.h>
#include <net/netfilter/nf_nat_masquerade.h>
struct nft_masq {
u32 flags;
enum nft_registers sreg_proto_min:8;
enum nft_registers sreg_proto_max:8;
};
static const struct nla_policy nft_masq_policy[NFTA_MASQ_MAX + 1] = {
[NFTA_MASQ_FLAGS] = { .type = NLA_U32 },
[NFTA_MASQ_REG_PROTO_MIN] = { .type = NLA_U32 },
[NFTA_MASQ_REG_PROTO_MAX] = { .type = NLA_U32 },
};
static int nft_masq_validate(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nft_data **data)
{
int err;
err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT);
if (err < 0)
return err;
return nft_chain_validate_hooks(ctx->chain,
(1 << NF_INET_POST_ROUTING));
}
static int nft_masq_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
u32 plen = FIELD_SIZEOF(struct nf_nat_range, min_addr.all);
struct nft_masq *priv = nft_expr_priv(expr);
int err;
if (tb[NFTA_MASQ_FLAGS]) {
priv->flags = ntohl(nla_get_be32(tb[NFTA_MASQ_FLAGS]));
if (priv->flags & ~NF_NAT_RANGE_MASK)
return -EINVAL;
}
if (tb[NFTA_MASQ_REG_PROTO_MIN]) {
priv->sreg_proto_min =
nft_parse_register(tb[NFTA_MASQ_REG_PROTO_MIN]);
err = nft_validate_register_load(priv->sreg_proto_min, plen);
if (err < 0)
return err;
if (tb[NFTA_MASQ_REG_PROTO_MAX]) {
priv->sreg_proto_max =
nft_parse_register(tb[NFTA_MASQ_REG_PROTO_MAX]);
err = nft_validate_register_load(priv->sreg_proto_max,
plen);
if (err < 0)
return err;
} else {
priv->sreg_proto_max = priv->sreg_proto_min;
}
}
return nf_ct_netns_get(ctx->net, ctx->family);
}
static int nft_masq_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
const struct nft_masq *priv = nft_expr_priv(expr);
if (priv->flags != 0 &&
nla_put_be32(skb, NFTA_MASQ_FLAGS, htonl(priv->flags)))
goto nla_put_failure;
if (priv->sreg_proto_min) {
if (nft_dump_register(skb, NFTA_MASQ_REG_PROTO_MIN,
priv->sreg_proto_min) ||
nft_dump_register(skb, NFTA_MASQ_REG_PROTO_MAX,
priv->sreg_proto_max))
goto nla_put_failure;
}
return 0;
nla_put_failure:
return -1;
}
static void nft_masq_ipv4_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
struct nft_masq *priv = nft_expr_priv(expr);
struct nf_nat_range2 range;
memset(&range, 0, sizeof(range));
range.flags = priv->flags;
if (priv->sreg_proto_min) {
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]);
}
regs->verdict.code = nf_nat_masquerade_ipv4(pkt->skb, nft_hook(pkt),
&range, nft_out(pkt));
}
static void
nft_masq_ipv4_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
{
nf_ct_netns_put(ctx->net, NFPROTO_IPV4);
}
static struct nft_expr_type nft_masq_ipv4_type;
static const struct nft_expr_ops nft_masq_ipv4_ops = {
.type = &nft_masq_ipv4_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_masq)),
.eval = nft_masq_ipv4_eval,
.init = nft_masq_init,
.destroy = nft_masq_ipv4_destroy,
.dump = nft_masq_dump,
.validate = nft_masq_validate,
};
static struct nft_expr_type nft_masq_ipv4_type __read_mostly = {
.family = NFPROTO_IPV4,
.name = "masq",
.ops = &nft_masq_ipv4_ops,
.policy = nft_masq_policy,
.maxattr = NFTA_MASQ_MAX,
.owner = THIS_MODULE,
};
#ifdef CONFIG_NF_TABLES_IPV6
static void nft_masq_ipv6_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
struct nft_masq *priv = nft_expr_priv(expr);
struct nf_nat_range2 range;
memset(&range, 0, sizeof(range));
range.flags = priv->flags;
if (priv->sreg_proto_min) {
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]);
}
regs->verdict.code = nf_nat_masquerade_ipv6(pkt->skb, &range,
nft_out(pkt));
}
static void
nft_masq_ipv6_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
{
nf_ct_netns_put(ctx->net, NFPROTO_IPV6);
}
static struct nft_expr_type nft_masq_ipv6_type;
static const struct nft_expr_ops nft_masq_ipv6_ops = {
.type = &nft_masq_ipv6_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_masq)),
.eval = nft_masq_ipv6_eval,
.init = nft_masq_init,
.destroy = nft_masq_ipv6_destroy,
.dump = nft_masq_dump,
.validate = nft_masq_validate,
};
static struct nft_expr_type nft_masq_ipv6_type __read_mostly = {
.family = NFPROTO_IPV6,
.name = "masq",
.ops = &nft_masq_ipv6_ops,
.policy = nft_masq_policy,
.maxattr = NFTA_MASQ_MAX,
.owner = THIS_MODULE,
};
static int __init nft_masq_module_init_ipv6(void)
{
return nft_register_expr(&nft_masq_ipv6_type);
}
static void nft_masq_module_exit_ipv6(void)
{
nft_unregister_expr(&nft_masq_ipv6_type);
}
#else
static inline int nft_masq_module_init_ipv6(void) { return 0; }
static inline void nft_masq_module_exit_ipv6(void) {}
#endif
#ifdef CONFIG_NF_TABLES_INET
static void nft_masq_inet_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
switch (nft_pf(pkt)) {
case NFPROTO_IPV4:
return nft_masq_ipv4_eval(expr, regs, pkt);
case NFPROTO_IPV6:
return nft_masq_ipv6_eval(expr, regs, pkt);
}
WARN_ON_ONCE(1);
}
static void
nft_masq_inet_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
{
nf_ct_netns_put(ctx->net, NFPROTO_INET);
}
static struct nft_expr_type nft_masq_inet_type;
static const struct nft_expr_ops nft_masq_inet_ops = {
.type = &nft_masq_inet_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_masq)),
.eval = nft_masq_inet_eval,
.init = nft_masq_init,
.destroy = nft_masq_inet_destroy,
.dump = nft_masq_dump,
.validate = nft_masq_validate,
};
static struct nft_expr_type nft_masq_inet_type __read_mostly = {
.family = NFPROTO_INET,
.name = "masq",
.ops = &nft_masq_inet_ops,
.policy = nft_masq_policy,
.maxattr = NFTA_MASQ_MAX,
.owner = THIS_MODULE,
};
static int __init nft_masq_module_init_inet(void)
{
return nft_register_expr(&nft_masq_inet_type);
}
static void nft_masq_module_exit_inet(void)
{
nft_unregister_expr(&nft_masq_inet_type);
}
#else
static inline int nft_masq_module_init_inet(<
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