// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
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* Copyright (c) 2012 Pablo Neira Ayuso <pablo@netfilter.org>
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* Copyright (c) 2012 Intel Corporation
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/skbuff.h>
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#include <linux/ip.h>
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#include <linux/string.h>
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#include <linux/netlink.h>
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#include <linux/netfilter.h>
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#include <linux/netfilter_ipv4.h>
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#include <linux/netfilter/nfnetlink.h>
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#include <linux/netfilter/nf_tables.h>
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#include <net/netfilter/nf_conntrack.h>
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#include <net/netfilter/nf_nat.h>
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#include <net/netfilter/nf_tables.h>
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#include <net/ip.h>
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struct nft_nat {
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u8 sreg_addr_min;
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u8 sreg_addr_max;
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u8 sreg_proto_min;
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u8 sreg_proto_max;
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enum nf_nat_manip_type type:8;
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u8 family;
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u16 flags;
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};
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static void nft_nat_setup_addr(struct nf_nat_range2 *range,
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const struct nft_regs *regs,
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const struct nft_nat *priv)
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{
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switch (priv->family) {
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case AF_INET:
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range->min_addr.ip = (__force __be32)
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regs->data[priv->sreg_addr_min];
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range->max_addr.ip = (__force __be32)
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regs->data[priv->sreg_addr_max];
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break;
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case AF_INET6:
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memcpy(range->min_addr.ip6, ®s->data[priv->sreg_addr_min],
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sizeof(range->min_addr.ip6));
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memcpy(range->max_addr.ip6, ®s->data[priv->sreg_addr_max],
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sizeof(range->max_addr.ip6));
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break;
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}
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}
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static void nft_nat_setup_proto(struct nf_nat_range2 *range,
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const struct nft_regs *regs,
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const struct nft_nat *priv)
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{
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range->min_proto.all = (__force __be16)
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nft_reg_load16(®s->data[priv->sreg_proto_min]);
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range->max_proto.all = (__force __be16)
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nft_reg_load16(®s->data[priv->sreg_proto_max]);
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}
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static void nft_nat_setup_netmap(struct nf_nat_range2 *range,
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const struct nft_pktinfo *pkt,
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const struct nft_nat *priv)
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{
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struct sk_buff *skb = pkt->skb;
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union nf_inet_addr new_addr;
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__be32 netmask;
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int i, len = 0;
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switch (priv->type) {
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case NFT_NAT_SNAT:
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if (nft_pf(pkt) == NFPROTO_IPV4) {
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new_addr.ip = ip_hdr(skb)->saddr;
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len = sizeof(struct in_addr);
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} else {
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new_addr.in6 = ipv6_hdr(skb)->saddr;
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len = sizeof(struct in6_addr);
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}
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break;
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case NFT_NAT_DNAT:
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if (nft_pf(pkt) == NFPROTO_IPV4) {
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new_addr.ip = ip_hdr(skb)->daddr;
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len = sizeof(struct in_addr);
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} else {
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new_addr.in6 = ipv6_hdr(skb)->daddr;
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len = sizeof(struct in6_addr);
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}
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break;
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}
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for (i = 0; i < len / sizeof(__be32); i++) {
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netmask = ~(range->min_addr.ip6[i] ^ range->max_addr.ip6[i]);
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new_addr.ip6[i] &= ~netmask;
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new_addr.ip6[i] |= range->min_addr.ip6[i] & netmask;
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}
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range->min_addr = new_addr;
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range->max_addr = new_addr;
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}
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static void nft_nat_eval(const struct nft_expr *expr,
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struct nft_regs *regs,
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const struct nft_pktinfo *pkt)
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{
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const struct nft_nat *priv = nft_expr_priv(expr);
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enum ip_conntrack_info ctinfo;
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struct nf_conn *ct = nf_ct_get(pkt->skb, &ctinfo);
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struct nf_nat_range2 range;
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memset(&range, 0, sizeof(range));
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if (priv->sreg_addr_min) {
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nft_nat_setup_addr(&range, regs, priv);
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if (priv->flags & NF_NAT_RANGE_NETMAP)
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nft_nat_setup_netmap(&range, pkt, priv);
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}
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if (priv->sreg_proto_min)
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nft_nat_setup_proto(&range, regs, priv);
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range.flags = priv->flags;
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regs->verdict.code = nf_nat_setup_info(ct, &range, priv->type);
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}
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static const struct nla_policy nft_nat_policy[NFTA_NAT_MAX + 1] = {
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[NFTA_NAT_TYPE] = { .type = NLA_U32 },
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[NFTA_NAT_FAMILY] = { .type = NLA_U32 },
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[NFTA_NAT_REG_ADDR_MIN] = { .type = NLA_U32 },
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[NFTA_NAT_REG_ADDR_MAX] = { .type = NLA_U32 },
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[NFTA_NAT_REG_PROTO_MIN] = { .type = NLA_U32 },
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[NFTA_NAT_REG_PROTO_MAX] = { .type = NLA_U32 },
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[NFTA_NAT_FLAGS] = { .type = NLA_U32 },
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};
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static int nft_nat_validate(const struct nft_ctx *ctx,
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const struct nft_expr *expr,
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const struct nft_data **data)
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{
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struct nft_nat *priv = nft_expr_priv(expr);
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int err;
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err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT);
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if (err < 0)
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return err;
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switch (priv->type) {
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case NFT_NAT_SNAT:
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err = nft_chain_validate_hooks(ctx->chain,
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(1 << NF_INET_POST_ROUTING) |
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(1 << NF_INET_LOCAL_IN));
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break;
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case NFT_NAT_DNAT:
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err = nft_chain_validate_hooks(ctx->chain,
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(1 << NF_INET_PRE_ROUTING) |
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(1 << NF_INET_LOCAL_OUT));
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break;
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}
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return err;
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}
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static int nft_nat_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
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const struct nlattr * const tb[])
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{
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struct nft_nat *priv = nft_expr_priv(expr);
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unsigned int alen, plen;
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u32 family;
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int err;
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if (tb[NFTA_NAT_TYPE] == NULL ||
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(tb[NFTA_NAT_REG_ADDR_MIN] == NULL &&
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tb[NFTA_NAT_REG_PROTO_MIN] == NULL))
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return -EINVAL;
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switch (ntohl(nla_get_be32(tb[NFTA_NAT_TYPE]))) {
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case NFT_NAT_SNAT:
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priv->type = NF_NAT_MANIP_SRC;
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break;
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case NFT_NAT_DNAT:
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priv->type = NF_NAT_MANIP_DST;
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break;
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default:
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return -EOPNOTSUPP;
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}
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if (tb[NFTA_NAT_FAMILY] == NULL)
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return -EINVAL;
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family = ntohl(nla_get_be32(tb[NFTA_NAT_FAMILY]));
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if (ctx->family != NFPROTO_INET && ctx->family != family)
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return -EOPNOTSUPP;
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switch (family) {
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case NFPROTO_IPV4:
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alen = sizeof_field(struct nf_nat_range, min_addr.ip);
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break;
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case NFPROTO_IPV6:
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alen = sizeof_field(struct nf_nat_range, min_addr.ip6);
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break;
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default:
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if (tb[NFTA_NAT_REG_ADDR_MIN])
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return -EAFNOSUPPORT;
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break;
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}
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priv->family = family;
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if (tb[NFTA_NAT_REG_ADDR_MIN]) {
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err = nft_parse_register_load(tb[NFTA_NAT_REG_ADDR_MIN],
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&priv->sreg_addr_min, alen);
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if (err < 0)
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return err;
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if (tb[NFTA_NAT_REG_ADDR_MAX]) {
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err = nft_parse_register_load(tb[NFTA_NAT_REG_ADDR_MAX],
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&priv->sreg_addr_max,
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alen);
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if (err < 0)
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return err;
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} else {
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priv->sreg_addr_max = priv->sreg_addr_min;
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}
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priv->flags |= NF_NAT_RANGE_MAP_IPS;
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}
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plen = sizeof_field(struct nf_nat_range, min_addr.all);
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if (tb[NFTA_NAT_REG_PROTO_MIN]) {
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err = nft_parse_register_load(tb[NFTA_NAT_REG_PROTO_MIN],
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&priv->sreg_proto_min, plen);
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if (err < 0)
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return err;
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if (tb[NFTA_NAT_REG_PROTO_MAX]) {
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err = nft_parse_register_load(tb[NFTA_NAT_REG_PROTO_MAX],
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&priv->sreg_proto_max,
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plen);
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if (err < 0)
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return err;
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} else {
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priv->sreg_proto_max = priv->sreg_proto_min;
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}
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priv->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
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}
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if (tb[NFTA_NAT_FLAGS]) {
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priv->flags |= ntohl(nla_get_be32(tb[NFTA_NAT_FLAGS]));
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if (priv->flags & ~NF_NAT_RANGE_MASK)
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return -EOPNOTSUPP;
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}
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return nf_ct_netns_get(ctx->net, family);
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}
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static int nft_nat_dump(struct sk_buff *skb, const struct nft_expr *expr)
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{
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const struct nft_nat *priv = nft_expr_priv(expr);
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switch (priv->type) {
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case NF_NAT_MANIP_SRC:
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if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_SNAT)))
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goto nla_put_failure;
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break;
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case NF_NAT_MANIP_DST:
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if (nla_put_be32(skb, NFTA_NAT_TYPE, htonl(NFT_NAT_DNAT)))
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goto nla_put_failure;
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break;
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}
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if (nla_put_be32(skb, NFTA_NAT_FAMILY, htonl(priv->family)))
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goto nla_put_failure;
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if (priv->sreg_addr_min) {
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if (nft_dump_register(skb, NFTA_NAT_REG_ADDR_MIN,
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priv->sreg_addr_min) ||
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nft_dump_register(skb, NFTA_NAT_REG_ADDR_MAX,
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priv->sreg_addr_max))
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goto nla_put_failure;
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}
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if (priv->sreg_proto_min) {
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if (nft_dump_register(skb, NFTA_NAT_REG_PROTO_MIN,
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priv->sreg_proto_min) ||
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nft_dump_register(skb, NFTA_NAT_REG_PROTO_MAX,
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priv->sreg_proto_max))
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goto nla_put_failure;
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}
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if (priv->flags != 0) {
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if (nla_put_be32(skb, NFTA_NAT_FLAGS, htonl(priv->flags)))
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goto nla_put_failure;
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}
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return 0;
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nla_put_failure:
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return -1;
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}
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static void
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nft_nat_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
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{
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const struct nft_nat *priv = nft_expr_priv(expr);
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nf_ct_netns_put(ctx->net, priv->family);
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}
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static struct nft_expr_type nft_nat_type;
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static const struct nft_expr_ops nft_nat_ops = {
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.type = &nft_nat_type,
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.size = NFT_EXPR_SIZE(sizeof(struct nft_nat)),
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.eval = nft_nat_eval,
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.init = nft_nat_init,
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.destroy = nft_nat_destroy,
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.dump = nft_nat_dump,
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.validate = nft_nat_validate,
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};
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static struct nft_expr_type nft_nat_type __read_mostly = {
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.name = "nat",
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.ops = &nft_nat_ops,
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.policy = nft_nat_policy,
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.maxattr = NFTA_NAT_MAX,
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.owner = THIS_MODULE,
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};
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#ifdef CONFIG_NF_TABLES_INET
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static void nft_nat_inet_eval(const struct nft_expr *expr,
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struct nft_regs *regs,
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const struct nft_pktinfo *pkt)
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{
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const struct nft_nat *priv = nft_expr_priv(expr);
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if (priv->family == nft_pf(pkt) ||
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priv->family == NFPROTO_INET)
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nft_nat_eval(expr, regs, pkt);
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}
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static const struct nft_expr_ops nft_nat_inet_ops = {
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.type = &nft_nat_type,
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.size = NFT_EXPR_SIZE(sizeof(struct nft_nat)),
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.eval = nft_nat_inet_eval,
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.init = nft_nat_init,
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.destroy = nft_nat_destroy,
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.dump = nft_nat_dump,
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.validate = nft_nat_validate,
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};
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static struct nft_expr_type nft_inet_nat_type __read_mostly = {
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.name = "nat",
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.family = NFPROTO_INET,
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.ops = &nft_nat_inet_ops,
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.policy = nft_nat_policy,
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.maxattr = NFTA_NAT_MAX,
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.owner = THIS_MODULE,
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};
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static int nft_nat_inet_module_init(void)
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{
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return nft_register_expr(&nft_inet_nat_type);
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}
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static void nft_nat_inet_module_exit(void)
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{
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nft_unregister_expr(&nft_inet_nat_type);
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}
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#else
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static int nft_nat_inet_module_init(void) { return 0; }
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static void nft_nat_inet_module_exit(void) { }
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#endif
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static int __init nft_nat_module_init(void)
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{
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int ret = nft_nat_inet_module_init();
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if (ret)
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return ret;
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ret = nft_register_expr(&nft_nat_type);
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if (ret)
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nft_nat_inet_module_exit();
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return ret;
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}
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static void __exit nft_nat_module_exit(void)
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{
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nft_nat_inet_module_exit();
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nft_unregister_expr(&nft_nat_type);
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}
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module_init(nft_nat_module_init);
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module_exit(nft_nat_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>");
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MODULE_ALIAS_NFT_EXPR("nat");
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MODULE_DESCRIPTION("Network Address Translation support");
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