net/netfilter/nft_reject_inet.c

   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
  20 static 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
  64 static 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
 100 static 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
 120 nla_put_failure:
 121         return -1;
 122 }
 123
 124 static struct nft_expr_type nft_reject_inet_type;
 125 static 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
 134 static 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
 143 static int __init nft_reject_inet_module_init(void)
 144 {
 145         return nft_register_expr(&nft_reject_inet_type);
 146 }
 147
 148 static void __exit nft_reject_inet_module_exit(void)
 149 {
 150         nft_unregister_expr(&nft_reject_inet_type);
 151 }
 152
 153 module_init(nft_reject_inet_module_init);
 154 module_exit(nft_reject_inet_module_exit);
 155
 156 MODULE_LICENSE("GPL");
 157 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 158 MODULE_ALIAS_NFT_AF_EXPR(1, "reject");