diff options
Diffstat (limited to 'net/netfilter/nft_masq.c')
-rw-r--r-- | net/netfilter/nft_masq.c | 289 |
1 files changed, 289 insertions, 0 deletions
diff --git a/net/netfilter/nft_masq.c b/net/netfilter/nft_masq.c new file mode 100644 index 0000000000..8a14aaca93 --- /dev/null +++ b/net/netfilter/nft_masq.c @@ -0,0 +1,289 @@ +// 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; + u8 sreg_proto_min; + u8 sreg_proto_max; +}; + +static const struct nla_policy nft_masq_policy[NFTA_MASQ_MAX + 1] = { + [NFTA_MASQ_FLAGS] = + NLA_POLICY_MASK(NLA_BE32, NF_NAT_RANGE_MASK), + [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 = sizeof_field(struct nf_nat_range, min_proto.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 (tb[NFTA_MASQ_REG_PROTO_MIN]) { + err = nft_parse_register_load(tb[NFTA_MASQ_REG_PROTO_MIN], + &priv->sreg_proto_min, plen); + if (err < 0) + return err; + + if (tb[NFTA_MASQ_REG_PROTO_MAX]) { + err = nft_parse_register_load(tb[NFTA_MASQ_REG_PROTO_MAX], + &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, bool reset) +{ + 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_eval(const struct nft_expr *expr, + struct nft_regs *regs, + const struct nft_pktinfo *pkt) +{ + const 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]); + } + + switch (nft_pf(pkt)) { + case NFPROTO_IPV4: + regs->verdict.code = nf_nat_masquerade_ipv4(pkt->skb, + nft_hook(pkt), + &range, + nft_out(pkt)); + break; +#ifdef CONFIG_NF_TABLES_IPV6 + case NFPROTO_IPV6: + regs->verdict.code = nf_nat_masquerade_ipv6(pkt->skb, &range, + nft_out(pkt)); + break; +#endif + default: + WARN_ON_ONCE(1); + break; + } +} + +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_eval, + .init = nft_masq_init, + .destroy = nft_masq_ipv4_destroy, + .dump = nft_masq_dump, + .validate = nft_masq_validate, + .reduce = NFT_REDUCE_READONLY, +}; + +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_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_eval, + .init = nft_masq_init, + .destroy = nft_masq_ipv6_destroy, + .dump = nft_masq_dump, + .validate = nft_masq_validate, + .reduce = NFT_REDUCE_READONLY, +}; + +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_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_eval, + .init = nft_masq_init, + .destroy = nft_masq_inet_destroy, + .dump = nft_masq_dump, + .validate = nft_masq_validate, + .reduce = NFT_REDUCE_READONLY, +}; + +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(void) { return 0; } +static inline void nft_masq_module_exit_inet(void) {} +#endif + +static int __init nft_masq_module_init(void) +{ + int ret; + + ret = nft_masq_module_init_ipv6(); + if (ret < 0) + return ret; + + ret = nft_masq_module_init_inet(); + if (ret < 0) { + nft_masq_module_exit_ipv6(); + return ret; + } + + ret = nft_register_expr(&nft_masq_ipv4_type); + if (ret < 0) { + nft_masq_module_exit_inet(); + nft_masq_module_exit_ipv6(); + return ret; + } + + ret = nf_nat_masquerade_inet_register_notifiers(); + if (ret < 0) { + nft_masq_module_exit_ipv6(); + nft_masq_module_exit_inet(); + nft_unregister_expr(&nft_masq_ipv4_type); + return ret; + } + + return ret; +} + +static void __exit nft_masq_module_exit(void) +{ + nft_masq_module_exit_ipv6(); + nft_masq_module_exit_inet(); + nft_unregister_expr(&nft_masq_ipv4_type); + nf_nat_masquerade_inet_unregister_notifiers(); +} + +module_init(nft_masq_module_init); +module_exit(nft_masq_module_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Arturo Borrero Gonzalez <arturo@debian.org>"); +MODULE_ALIAS_NFT_EXPR("masq"); +MODULE_DESCRIPTION("Netfilter nftables masquerade expression support"); 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