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 {
  29         return nft_chain_validate_hooks(ctx->chain,
  30                                         (1 << NF_INET_LOCAL_IN) |
  31                                         (1 << NF_INET_FORWARD) |
  32                                         (1 << NF_INET_LOCAL_OUT) |
  33                                         (1 << NF_INET_PRE_ROUTING));
  34 }
  35 EXPORT_SYMBOL_GPL(nft_reject_validate);
  36
  37 int nft_reject_init(const struct nft_ctx *ctx,
  38                     const struct nft_expr *expr,
  39                     const struct nlattr * const tb[])
  40 {
  41         struct nft_reject *priv = nft_expr_priv(expr);
  42         int icmp_code;
  43
  44         if (tb[NFTA_REJECT_TYPE] == NULL)
  45                 return -EINVAL;
  46
  47         priv->type = ntohl(nla_get_be32(tb[NFTA_REJECT_TYPE]));
  48         switch (priv->type) {
  49         case NFT_REJECT_ICMP_UNREACH:
  50         case NFT_REJECT_ICMPX_UNREACH:
  51                 if (tb[NFTA_REJECT_ICMP_CODE] == NULL)
  52                         return -EINVAL;
  53
  54                 icmp_code = nla_get_u8(tb[NFTA_REJECT_ICMP_CODE]);
  55                 if (priv->type == NFT_REJECT_ICMPX_UNREACH &&
  56                     icmp_code > NFT_REJECT_ICMPX_MAX)
  57                         return -EINVAL;
  58
  59                 priv->icmp_code = icmp_code;
  60                 break;
  61         case NFT_REJECT_TCP_RST:
  62                 break;
  63         default:
  64                 return -EINVAL;
  65         }
  66
  67         return 0;
  68 }
  69 EXPORT_SYMBOL_GPL(nft_reject_init);
  70
  71 int nft_reject_dump(struct sk_buff *skb,
  72                     const struct nft_expr *expr, bool reset)
  73 {
  74         const struct nft_reject *priv = nft_expr_priv(expr);
  75
  76         if (nla_put_be32(skb, NFTA_REJECT_TYPE, htonl(priv->type)))
  77                 goto nla_put_failure;
  78
  79         switch (priv->type) {
  80         case NFT_REJECT_ICMP_UNREACH:
  81         case NFT_REJECT_ICMPX_UNREACH:
  82                 if (nla_put_u8(skb, NFTA_REJECT_ICMP_CODE, priv->icmp_code))
  83                         goto nla_put_failure;
  84                 break;
  85         default:
  86                 break;
  87         }
  88
  89         return 0;
  90
  91 nla_put_failure:
  92         return -1;
  93 }
  94 EXPORT_SYMBOL_GPL(nft_reject_dump);
  95
  96 static u8 icmp_code_v4[NFT_REJECT_ICMPX_MAX + 1] = {
  97         [NFT_REJECT_ICMPX_NO_ROUTE]             = ICMP_NET_UNREACH,
  98         [NFT_REJECT_ICMPX_PORT_UNREACH]         = ICMP_PORT_UNREACH,
  99         [NFT_REJECT_ICMPX_HOST_UNREACH]         = ICMP_HOST_UNREACH,
 100         [NFT_REJECT_ICMPX_ADMIN_PROHIBITED]     = ICMP_PKT_FILTERED,
 101 };
 102
 103 int nft_reject_icmp_code(u8 code)
 104 {
 105         if (WARN_ON_ONCE(code > NFT_REJECT_ICMPX_MAX))
 106                 return ICMP_NET_UNREACH;
 107
 108         return icmp_code_v4[code];
 109 }
 110
 111 EXPORT_SYMBOL_GPL(nft_reject_icmp_code);
 112
 113
 114 static u8 icmp_code_v6[NFT_REJECT_ICMPX_MAX + 1] = {
 115         [NFT_REJECT_ICMPX_NO_ROUTE]             = ICMPV6_NOROUTE,
 116         [NFT_REJECT_ICMPX_PORT_UNREACH]         = ICMPV6_PORT_UNREACH,
 117         [NFT_REJECT_ICMPX_HOST_UNREACH]         = ICMPV6_ADDR_UNREACH,
 118         [NFT_REJECT_ICMPX_ADMIN_PROHIBITED]     = ICMPV6_ADM_PROHIBITED,
 119 };
 120
 121 int nft_reject_icmpv6_code(u8 code)
 122 {
 123         if (WARN_ON_ONCE(code > NFT_REJECT_ICMPX_MAX))
 124                 return ICMPV6_NOROUTE;
 125
 126         return icmp_code_v6[code];
 127 }
 128
 129 EXPORT_SYMBOL_GPL(nft_reject_icmpv6_code);
 130
 131 MODULE_LICENSE("GPL");
 132 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 133 MODULE_DESCRIPTION("Netfilter x_tables over nftables module");