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;
  70
  71         if (tb[NFTA_REJECT_TYPE] == NULL)
  72                 return -EINVAL;
  73
  74         priv->type = ntohl(nla_get_be32(tb[NFTA_REJECT_TYPE]));
  75         switch (priv->type) {
  76         case NFT_REJECT_ICMP_UNREACH:
  77         case NFT_REJECT_ICMPX_UNREACH:
  78                 if (tb[NFTA_REJECT_ICMP_CODE] == NULL)
  79                         return -EINVAL;
  80
  81                 icmp_code = nla_get_u8(tb[NFTA_REJECT_ICMP_CODE]);
  82                 if (priv->type == NFT_REJECT_ICMPX_UNREACH &&
  83                     icmp_code > NFT_REJECT_ICMPX_MAX)
  84                         return -EINVAL;
  85
  86                 priv->icmp_code = icmp_code;
  87                 break;
  88         case NFT_REJECT_TCP_RST:
  89                 break;
  90         default:
  91                 return -EINVAL;
  92         }
  93         return 0;
  94 }
  95
  96 static int nft_reject_inet_dump(struct sk_buff *skb,
  97                                 const struct nft_expr *expr)
  98 {
  99         const struct nft_reject *priv = nft_expr_priv(expr);
 100
 101         if (nla_put_be32(skb, NFTA_REJECT_TYPE, htonl(priv->type)))
 102                 goto nla_put_failure;
 103
 104         switch (priv->type) {
 105         case NFT_REJECT_ICMP_UNREACH:
 106         case NFT_REJECT_ICMPX_UNREACH:
 107                 if (nla_put_u8(skb, NFTA_REJECT_ICMP_CODE, priv->icmp_code))
 108                         goto nla_put_failure;
 109                 break;
 110         default:
 111                 break;
 112         }
 113
 114         return 0;
 115
 116 nla_put_failure:
 117         return -1;
 118 }
 119
 120 static struct nft_expr_type nft_reject_inet_type;
 121 static const struct nft_expr_ops nft_reject_inet_ops = {
 122         .type           = &nft_reject_inet_type,
 123         .size           = NFT_EXPR_SIZE(sizeof(struct nft_reject)),
 124         .eval           = nft_reject_inet_eval,
 125         .init           = nft_reject_inet_init,
 126         .dump           = nft_reject_inet_dump,
 127         .validate       = nft_reject_validate,
 128 };
 129
 130 static struct nft_expr_type nft_reject_inet_type __read_mostly = {
 131         .family         = NFPROTO_INET,
 132         .name           = "reject",
 133         .ops            = &nft_reject_inet_ops,
 134         .policy         = nft_reject_policy,
 135         .maxattr        = NFTA_REJECT_MAX,
 136         .owner          = THIS_MODULE,
 137 };
 138
 139 static int __init nft_reject_inet_module_init(void)
 140 {
 141         return nft_register_expr(&nft_reject_inet_type);
 142 }
 143
 144 static void __exit nft_reject_inet_module_exit(void)
 145 {
 146         nft_unregister_expr(&nft_reject_inet_type);
 147 }
 148
 149 module_init(nft_reject_inet_module_init);
 150 module_exit(nft_reject_inet_module_exit);
 151
 152 MODULE_LICENSE("GPL");
 153 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 154 MODULE_ALIAS_NFT_AF_EXPR(1, "reject");