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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_nat.h>
- #include <net/netfilter/nf_nat_redirect.h>
- #include <net/netfilter/nf_tables.h>
- struct nft_redir {
- enum nft_registers sreg_proto_min:8;
- enum nft_registers sreg_proto_max:8;
- u16 flags;
- };
- static const struct nla_policy nft_redir_policy[NFTA_REDIR_MAX + 1] = {
- [NFTA_REDIR_REG_PROTO_MIN] = { .type = NLA_U32 },
- [NFTA_REDIR_REG_PROTO_MAX] = { .type = NLA_U32 },
- [NFTA_REDIR_FLAGS] = { .type = NLA_U32 },
- };
- static int nft_redir_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_PRE_ROUTING) |
- (1 << NF_INET_LOCAL_OUT));
- }
- static int nft_redir_init(const struct nft_ctx *ctx,
- const struct nft_expr *expr,
- const struct nlattr * const tb[])
- {
- struct nft_redir *priv = nft_expr_priv(expr);
- unsigned int plen;
- int err;
- plen = sizeof_field(struct nf_nat_range, min_addr.all);
- if (tb[NFTA_REDIR_REG_PROTO_MIN]) {
- priv->sreg_proto_min =
- nft_parse_register(tb[NFTA_REDIR_REG_PROTO_MIN]);
- err = nft_validate_register_load(priv->sreg_proto_min, plen);
- if (err < 0)
- return err;
- if (tb[NFTA_REDIR_REG_PROTO_MAX]) {
- priv->sreg_proto_max =
- nft_parse_register(tb[NFTA_REDIR_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;
- }
- }
- if (tb[NFTA_REDIR_FLAGS]) {
- priv->flags = ntohl(nla_get_be32(tb[NFTA_REDIR_FLAGS]));
- if (priv->flags & ~NF_NAT_RANGE_MASK)
- return -EINVAL;
- }
- return nf_ct_netns_get(ctx->net, ctx->family);
- }
- static int nft_redir_dump(struct sk_buff *skb, const struct nft_expr *expr)
- {
- const struct nft_redir *priv = nft_expr_priv(expr);
- if (priv->sreg_proto_min) {
- if (nft_dump_register(skb, NFTA_REDIR_REG_PROTO_MIN,
- priv->sreg_proto_min))
- goto nla_put_failure;
- if (nft_dump_register(skb, NFTA_REDIR_REG_PROTO_MAX,
- priv->sreg_proto_max))
- goto nla_put_failure;
- }
- if (priv->flags != 0 &&
- nla_put_be32(skb, NFTA_REDIR_FLAGS, htonl(priv->flags)))
- goto nla_put_failure;
- return 0;
- nla_put_failure:
- return -1;
- }
- static void nft_redir_ipv4_eval(const struct nft_expr *expr,
- struct nft_regs *regs,
- const struct nft_pktinfo *pkt)
- {
- struct nft_redir *priv = nft_expr_priv(expr);
- struct nf_nat_ipv4_multi_range_compat mr;
- memset(&mr, 0, sizeof(mr));
- if (priv->sreg_proto_min) {
- mr.range[0].min.all = (__force __be16)nft_reg_load16(
- ®s->data[priv->sreg_proto_min]);
- mr.range[0].max.all = (__force __be16)nft_reg_load16(
- ®s->data[priv->sreg_proto_max]);
- mr.range[0].flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
- }
- mr.range[0].flags |= priv->flags;
- regs->verdict.code = nf_nat_redirect_ipv4(pkt->skb, &mr, nft_hook(pkt));
- }
- static void
- nft_redir_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_redir_ipv4_type;
- static const struct nft_expr_ops nft_redir_ipv4_ops = {
- .type = &nft_redir_ipv4_type,
- .size = NFT_EXPR_SIZE(sizeof(struct nft_redir)),
- .eval = nft_redir_ipv4_eval,
- .init = nft_redir_init,
- .destroy = nft_redir_ipv4_destroy,
- .dump = nft_redir_dump,
- .validate = nft_redir_validate,
- };
- static struct nft_expr_type nft_redir_ipv4_type __read_mostly = {
- .family = NFPROTO_IPV4,
- .name = "redir",
- .ops = &nft_redir_ipv4_ops,
- .policy = nft_redir_policy,
- .maxattr = NFTA_REDIR_MAX,
- .owner = THIS_MODULE,
- };
- #ifdef CONFIG_NF_TABLES_IPV6
- static void nft_redir_ipv6_eval(const struct nft_expr *expr,
- struct nft_regs *regs,
- const struct nft_pktinfo *pkt)
- {
- struct nft_redir *priv = nft_expr_priv(expr);
- struct nf_nat_range2 range;
- memset(&range, 0, sizeof(range));
- 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]);
- range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
- }
- range.flags |= priv->flags;
- regs->verdict.code =
- nf_nat_redirect_ipv6(pkt->skb, &range, nft_hook(pkt));
- }
- static void
- nft_redir_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_redir_ipv6_type;
- static const struct nft_expr_ops nft_redir_ipv6_ops = {
- .type = &nft_redir_ipv6_type,
- .size = NFT_EXPR_SIZE(sizeof(struct nft_redir)),
- .eval = nft_redir_ipv6_eval,
- .init = nft_redir_init,
- .destroy = nft_redir_ipv6_destroy,
- .dump = nft_redir_dump,
- .validate = nft_redir_validate,
- };
- static struct nft_expr_type nft_redir_ipv6_type __read_mostly = {
- .family = NFPROTO_IPV6,
- .name = "redir",
- .ops = &nft_redir_ipv6_ops,
- .policy = nft_redir_policy,
- .maxattr = NFTA_REDIR_MAX,
- .owner = THIS_MODULE,
- };
- #endif
- #ifdef CONFIG_NF_TABLES_INET
- static void nft_redir_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_redir_ipv4_eval(expr, regs, pkt);
- case NFPROTO_IPV6:
- return nft_redir_ipv6_eval(expr, regs, pkt);
- }
- WARN_ON_ONCE(1);
- }
- static void
- nft_redir_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_redir_inet_type;
- static const struct nft_expr_ops nft_redir_inet_ops = {
- .type = &nft_redir_inet_type,
- .size = NFT_EXPR_SIZE(sizeof(struct nft_redir)),
- .eval = nft_redir_inet_eval,
- .init = nft_redir_init,
- .destroy = nft_redir_inet_destroy,
- .dump = nft_redir_dump,
- .validate = nft_redir_validate,
- };
- static struct nft_expr_type nft_redir_inet_type __read_mostly = {
- .family = NFPROTO_INET,
- .name = "redir",
- .ops = &nft_redir_inet_ops,
- .policy = nft_redir_policy,
- .maxattr = NFTA_MASQ_MAX,
- .owner = THIS_MODULE,
- };
- static int __init nft_redir_module_init_inet(void)
- {
- return nft_register_expr(&nft_redir_inet_type);
- }
- #else
- static inline int nft_redir_module_init_inet(void) { return 0; }
- #endif
- static int __init nft_redir_module_init(void)
- {
- int ret = nft_register_expr(&nft_redir_ipv4_type);
- if (ret)
- return ret;
- #ifdef CONFIG_NF_TABLES_IPV6
- ret = nft_register_expr(&nft_redir_ipv6_type);
- if (ret) {
- nft_unregister_expr(&nft_redir_ipv4_type);
- return ret;
- }
- #endif
- ret = nft_redir_module_init_inet();
- if (ret < 0) {
- nft_unregister_expr(&nft_redir_ipv4_type);
- #ifdef CONFIG_NF_TABLES_IPV6
- nft_unregister_expr(&nft_redir_ipv6_type);
- #endif
- return ret;
- }
- return ret;
- }
- static void __exit nft_redir_module_exit(void)
- {
- nft_unregister_expr(&nft_redir_ipv4_type);
- #ifdef CONFIG_NF_TABLES_IPV6
- nft_unregister_expr(&nft_redir_ipv6_type);
- #endif
- #ifdef CONFIG_NF_TABLES_INET
- nft_unregister_expr(&nft_redir_inet_type);
- #endif
- }
- module_init(nft_redir_module_init);
- module_exit(nft_redir_module_exit);
- MODULE_LICENSE("GPL");
- MODULE_AUTHOR("Arturo Borrero Gonzalez <arturo@debian.org>");
- MODULE_ALIAS_NFT_EXPR("redir");
- MODULE_DESCRIPTION("Netfilter nftables redirect support");
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