net/netfilter/nft_reject.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
   4  * Copyright (c) 2013 Eric Leblond <eric@regit.org>
   5  *
   6  * Development of this code funded by Astaro AG (http://www.astaro.com/)
   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 <linux/icmp.h>
  18 #include <linux/icmpv6.h>
  19
  20 const struct nla_policy nft_reject_policy[NFTA_REJECT_MAX + 1] = {
  21         [NFTA_REJECT_TYPE]              = NLA_POLICY_MAX(NLA_BE32, 255),
  22         [NFTA_REJECT_ICMP_CODE]         = { .type = NLA_U8 },
  23 };
  24 EXPORT_SYMBOL_GPL(nft_reject_policy);
  25
  26 int nft_reject_validate(const struct nft_ctx *ctx,
  27                         const struct nft_expr *expr,
  28                         const struct nft_data **data)
  29 {
  30         return nft_chain_validate_hooks(ctx->chain,
  31                                         (1 << NF_INET_LOCAL_IN) |
  32                                         (1 << NF_INET_FORWARD) |
  33                                         (1 << NF_INET_LOCAL_OUT) |
  34                                         (1 << NF_INET_PRE_ROUTING));
  35 }
  36 EXPORT_SYMBOL_GPL(nft_reject_validate);
  37
  38 int nft_reject_init(const struct nft_ctx *ctx,
  39                     const struct nft_expr *expr,
  40                     const struct nlattr * const tb[])
  41 {
  42         struct nft_reject *priv = nft_expr_priv(expr);
  43         int icmp_code;
  44
  45         if (tb[NFTA_REJECT_TYPE] == NULL)
  46                 return -EINVAL;
  47
  48         priv->type = ntohl(nla_get_be32(tb[NFTA_REJECT_TYPE]));
  49         switch (priv->type) {
  50         case NFT_REJECT_ICMP_UNREACH:
  51         case NFT_REJECT_ICMPX_UNREACH:
  52                 if (tb[NFTA_REJECT_ICMP_CODE] == NULL)
  53                         return -EINVAL;
  54
  55                 icmp_code = nla_get_u8(tb[NFTA_REJECT_ICMP_CODE]);
  56                 if (priv->type == NFT_REJECT_ICMPX_UNREACH &&
  57                     icmp_code > NFT_REJECT_ICMPX_MAX)
  58                         return -EINVAL;
  59
  60                 priv->icmp_code = icmp_code;
  61                 break;
  62         case NFT_REJECT_TCP_RST:
  63                 break;
  64         default:
  65                 return -EINVAL;
  66         }
  67
  68         return 0;
  69 }
  70 EXPORT_SYMBOL_GPL(nft_reject_init);
  71
  72 int nft_reject_dump(struct sk_buff *skb,
  73                     const struct nft_expr *expr, bool reset)
  74 {
  75         const struct nft_reject *priv = nft_expr_priv(expr);
  76
  77         if (nla_put_be32(skb, NFTA_REJECT_TYPE, htonl(priv->type)))
  78                 goto nla_put_failure;
  79
  80         switch (priv->type) {
  81         case NFT_REJECT_ICMP_UNREACH:
  82         case NFT_REJECT_ICMPX_UNREACH:
  83                 if (nla_put_u8(skb, NFTA_REJECT_ICMP_CODE, priv->icmp_code))
  84                         goto nla_put_failure;
  85                 break;
  86         default:
  87                 break;
  88         }
  89
  90         return 0;
  91
  92 nla_put_failure:
  93         return -1;
  94 }
  95 EXPORT_SYMBOL_GPL(nft_reject_dump);
  96
  97 static u8 icmp_code_v4[NFT_REJECT_ICMPX_MAX + 1] = {
  98         [NFT_REJECT_ICMPX_NO_ROUTE]             = ICMP_NET_UNREACH,
  99         [NFT_REJECT_ICMPX_PORT_UNREACH]         = ICMP_PORT_UNREACH,
 100         [NFT_REJECT_ICMPX_HOST_UNREACH]         = ICMP_HOST_UNREACH,
 101         [NFT_REJECT_ICMPX_ADMIN_PROHIBITED]     = ICMP_PKT_FILTERED,
 102 };
 103
 104 int nft_reject_icmp_code(u8 code)
 105 {
 106         if (WARN_ON_ONCE(code > NFT_REJECT_ICMPX_MAX))
 107                 return ICMP_NET_UNREACH;
 108
 109         return icmp_code_v4[code];
 110 }
 111
 112 EXPORT_SYMBOL_GPL(nft_reject_icmp_code);
 113
 114
 115 static u8 icmp_code_v6[NFT_REJECT_ICMPX_MAX + 1] = {
 116         [NFT_REJECT_ICMPX_NO_ROUTE]             = ICMPV6_NOROUTE,
 117         [NFT_REJECT_ICMPX_PORT_UNREACH]         = ICMPV6_PORT_UNREACH,
 118         [NFT_REJECT_ICMPX_HOST_UNREACH]         = ICMPV6_ADDR_UNREACH,
 119         [NFT_REJECT_ICMPX_ADMIN_PROHIBITED]     = ICMPV6_ADM_PROHIBITED,
 120 };
 121
 122 int nft_reject_icmpv6_code(u8 code)
 123 {
 124         if (WARN_ON_ONCE(code > NFT_REJECT_ICMPX_MAX))
 125                 return ICMPV6_NOROUTE;
 126
 127         return icmp_code_v6[code];
 128 }
 129
 130 EXPORT_SYMBOL_GPL(nft_reject_icmpv6_code);
 131
 132 MODULE_LICENSE("GPL");
 133 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 134 MODULE_DESCRIPTION("Netfilter x_tables over nftables module");