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_data data[NFT_REG_MAX + 1],
  22                                  const struct nft_pktinfo *pkt)
  23 {
  24         struct nft_reject *priv = nft_expr_priv(expr);
  25         struct net *net = dev_net((pkt->in != NULL) ? pkt->in : pkt->out);
  26
  27         switch (pkt->ops->pf) {
  28         case NFPROTO_IPV4:
  29                 switch (priv->type) {
  30                 case NFT_REJECT_ICMP_UNREACH:
  31                         nf_send_unreach(pkt->skb, priv->icmp_code);
  32                         break;
  33                 case NFT_REJECT_TCP_RST:
  34                         nf_send_reset(pkt->skb, pkt->ops->hooknum);
  35                         break;
  36                 case NFT_REJECT_ICMPX_UNREACH:
  37                         nf_send_unreach(pkt->skb,
  38                                         nft_reject_icmp_code(priv->icmp_code));
  39                         break;
  40                 }
  41                 break;
  42         case NFPROTO_IPV6:
  43                 switch (priv->type) {
  44                 case NFT_REJECT_ICMP_UNREACH:
  45                         nf_send_unreach6(net, pkt->skb, priv->icmp_code,
  46                                          pkt->ops->hooknum);
  47                         break;
  48                 case NFT_REJECT_TCP_RST:
  49                         nf_send_reset6(net, pkt->skb, pkt->ops->hooknum);
  50                         break;
  51                 case NFT_REJECT_ICMPX_UNREACH:
  52                         nf_send_unreach6(net, pkt->skb,
  53                                          nft_reject_icmpv6_code(priv->icmp_code),
  54                                          pkt->ops->hooknum);
  55                         break;
  56                 }
  57                 break;
  58         }
  59         data[NFT_REG_VERDICT].verdict = NF_DROP;
  60 }
  61
  62 static int nft_reject_inet_init(const struct nft_ctx *ctx,
  63                                 const struct nft_expr *expr,
  64                                 const struct nlattr * const tb[])
  65 {
  66         struct nft_reject *priv = nft_expr_priv(expr);
  67         int icmp_code;
  68
  69         if (tb[NFTA_REJECT_TYPE] == NULL)
  70                 return -EINVAL;
  71
  72         priv->type = ntohl(nla_get_be32(tb[NFTA_REJECT_TYPE]));
  73         switch (priv->type) {
  74         case NFT_REJECT_ICMP_UNREACH:
  75         case NFT_REJECT_ICMPX_UNREACH:
  76                 if (tb[NFTA_REJECT_ICMP_CODE] == NULL)
  77                         return -EINVAL;
  78
  79                 icmp_code = nla_get_u8(tb[NFTA_REJECT_ICMP_CODE]);
  80                 if (priv->type == NFT_REJECT_ICMPX_UNREACH &&
  81                     icmp_code > NFT_REJECT_ICMPX_MAX)
  82                         return -EINVAL;
  83
  84                 priv->icmp_code = icmp_code;
  85                 break;
  86         case NFT_REJECT_TCP_RST:
  87                 break;
  88         default:
  89                 return -EINVAL;
  90         }
  91         return 0;
  92 }
  93
  94 static int nft_reject_inet_dump(struct sk_buff *skb,
  95                                 const struct nft_expr *expr)
  96 {
  97         const struct nft_reject *priv = nft_expr_priv(expr);
  98
  99         if (nla_put_be32(skb, NFTA_REJECT_TYPE, htonl(priv->type)))
 100                 goto nla_put_failure;
 101
 102         switch (priv->type) {
 103         case NFT_REJECT_ICMP_UNREACH:
 104         case NFT_REJECT_ICMPX_UNREACH:
 105                 if (nla_put_u8(skb, NFTA_REJECT_ICMP_CODE, priv->icmp_code))
 106                         goto nla_put_failure;
 107                 break;
 108         }
 109
 110         return 0;
 111
 112 nla_put_failure:
 113         return -1;
 114 }
 115
 116 static struct nft_expr_type nft_reject_inet_type;
 117 static const struct nft_expr_ops nft_reject_inet_ops = {
 118         .type           = &nft_reject_inet_type,
 119         .size           = NFT_EXPR_SIZE(sizeof(struct nft_reject)),
 120         .eval           = nft_reject_inet_eval,
 121         .init           = nft_reject_inet_init,
 122         .dump           = nft_reject_inet_dump,
 123 };
 124
 125 static struct nft_expr_type nft_reject_inet_type __read_mostly = {
 126         .family         = NFPROTO_INET,
 127         .name           = "reject",
 128         .ops            = &nft_reject_inet_ops,
 129         .policy         = nft_reject_policy,
 130         .maxattr        = NFTA_REJECT_MAX,
 131         .owner          = THIS_MODULE,
 132 };
 133
 134 static int __init nft_reject_inet_module_init(void)
 135 {
 136         return nft_register_expr(&nft_reject_inet_type);
 137 }
 138
 139 static void __exit nft_reject_inet_module_exit(void)
 140 {
 141         nft_unregister_expr(&nft_reject_inet_type);
 142 }
 143
 144 module_init(nft_reject_inet_module_init);
 145 module_exit(nft_reject_inet_module_exit);
 146
 147 MODULE_LICENSE("GPL");
 148 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 149 MODULE_ALIAS_NFT_AF_EXPR(1, "reject");