linux/net/netfilter/nft_reject_inet.c
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   1/*
   2 * Copyright (c) 2014 Patrick McHardy <kaber@trash.net>
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License version 2 as
   6 * published by the Free Software Foundation.
   7 */
   8
   9#include <linux/kernel.h>
  10#include <linux/init.h>
  11#include <linux/module.h>
  12#include <linux/netlink.h>
  13#include <linux/netfilter.h>
  14#include <linux/netfilter/nf_tables.h>
  15#include <net/netfilter/nf_tables.h>
  16#include <net/netfilter/nft_reject.h>
  17#include <net/netfilter/ipv4/nf_reject.h>
  18#include <net/netfilter/ipv6/nf_reject.h>
  19
  20static void nft_reject_inet_eval(const struct nft_expr *expr,
  21                                 struct nft_regs *regs,
  22                                 const struct nft_pktinfo *pkt)
  23{
  24        struct nft_reject *priv = nft_expr_priv(expr);
  25
  26        switch (nft_pf(pkt)) {
  27        case NFPROTO_IPV4:
  28                switch (priv->type) {
  29                case NFT_REJECT_ICMP_UNREACH:
  30                        nf_send_unreach(pkt->skb, priv->icmp_code,
  31                                        nft_hook(pkt));
  32                        break;
  33                case NFT_REJECT_TCP_RST:
  34                        nf_send_reset(nft_net(pkt), pkt->skb, nft_hook(pkt));
  35                        break;
  36                case NFT_REJECT_ICMPX_UNREACH:
  37                        nf_send_unreach(pkt->skb,
  38                                        nft_reject_icmp_code(priv->icmp_code),
  39                                        nft_hook(pkt));
  40                        break;
  41                }
  42                break;
  43        case NFPROTO_IPV6:
  44                switch (priv->type) {
  45                case NFT_REJECT_ICMP_UNREACH:
  46                        nf_send_unreach6(nft_net(pkt), pkt->skb,
  47                                         priv->icmp_code, nft_hook(pkt));
  48                        break;
  49                case NFT_REJECT_TCP_RST:
  50                        nf_send_reset6(nft_net(pkt), pkt->skb, nft_hook(pkt));
  51                        break;
  52                case NFT_REJECT_ICMPX_UNREACH:
  53                        nf_send_unreach6(nft_net(pkt), pkt->skb,
  54                                         nft_reject_icmpv6_code(priv->icmp_code),
  55                                         nft_hook(pkt));
  56                        break;
  57                }
  58                break;
  59        }
  60
  61        regs->verdict.code = NF_DROP;
  62}
  63
  64static int nft_reject_inet_init(const struct nft_ctx *ctx,
  65                                const struct nft_expr *expr,
  66                                const struct nlattr * const tb[])
  67{
  68        struct nft_reject *priv = nft_expr_priv(expr);
  69        int icmp_code, err;
  70
  71        err = nft_reject_validate(ctx, expr, NULL);
  72        if (err < 0)
  73                return err;
  74
  75        if (tb[NFTA_REJECT_TYPE] == NULL)
  76                return -EINVAL;
  77
  78        priv->type = ntohl(nla_get_be32(tb[NFTA_REJECT_TYPE]));
  79        switch (priv->type) {
  80        case NFT_REJECT_ICMP_UNREACH:
  81        case NFT_REJECT_ICMPX_UNREACH:
  82                if (tb[NFTA_REJECT_ICMP_CODE] == NULL)
  83                        return -EINVAL;
  84
  85                icmp_code = nla_get_u8(tb[NFTA_REJECT_ICMP_CODE]);
  86                if (priv->type == NFT_REJECT_ICMPX_UNREACH &&
  87                    icmp_code > NFT_REJECT_ICMPX_MAX)
  88                        return -EINVAL;
  89
  90                priv->icmp_code = icmp_code;
  91                break;
  92        case NFT_REJECT_TCP_RST:
  93                break;
  94        default:
  95                return -EINVAL;
  96        }
  97        return 0;
  98}
  99
 100static int nft_reject_inet_dump(struct sk_buff *skb,
 101                                const struct nft_expr *expr)
 102{
 103        const struct nft_reject *priv = nft_expr_priv(expr);
 104
 105        if (nla_put_be32(skb, NFTA_REJECT_TYPE, htonl(priv->type)))
 106                goto nla_put_failure;
 107
 108        switch (priv->type) {
 109        case NFT_REJECT_ICMP_UNREACH:
 110        case NFT_REJECT_ICMPX_UNREACH:
 111                if (nla_put_u8(skb, NFTA_REJECT_ICMP_CODE, priv->icmp_code))
 112                        goto nla_put_failure;
 113                break;
 114        default:
 115                break;
 116        }
 117
 118        return 0;
 119
 120nla_put_failure:
 121        return -1;
 122}
 123
 124static struct nft_expr_type nft_reject_inet_type;
 125static const struct nft_expr_ops nft_reject_inet_ops = {
 126        .type           = &nft_reject_inet_type,
 127        .size           = NFT_EXPR_SIZE(sizeof(struct nft_reject)),
 128        .eval           = nft_reject_inet_eval,
 129        .init           = nft_reject_inet_init,
 130        .dump           = nft_reject_inet_dump,
 131        .validate       = nft_reject_validate,
 132};
 133
 134static struct nft_expr_type nft_reject_inet_type __read_mostly = {
 135        .family         = NFPROTO_INET,
 136        .name           = "reject",
 137        .ops            = &nft_reject_inet_ops,
 138        .policy         = nft_reject_policy,
 139        .maxattr        = NFTA_REJECT_MAX,
 140        .owner          = THIS_MODULE,
 141};
 142
 143static int __init nft_reject_inet_module_init(void)
 144{
 145        return nft_register_expr(&nft_reject_inet_type);
 146}
 147
 148static void __exit nft_reject_inet_module_exit(void)
 149{
 150        nft_unregister_expr(&nft_reject_inet_type);
 151}
 152
 153module_init(nft_reject_inet_module_init);
 154module_exit(nft_reject_inet_module_exit);
 155
 156MODULE_LICENSE("GPL");
 157MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 158MODULE_ALIAS_NFT_AF_EXPR(1, "reject");
 159