net/netfilter/nft_reject_inet.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2014 Patrick McHardy <kaber@trash.net>
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/init.h>
   8 #include <linux/module.h>
   9 #include <linux/netlink.h>
  10 #include <linux/netfilter.h>
  11 #include <linux/netfilter/nf_tables.h>
  12 #include <net/netfilter/nf_tables.h>
  13 #include <net/netfilter/nft_reject.h>
  14 #include <net/netfilter/ipv4/nf_reject.h>
  15 #include <net/netfilter/ipv6/nf_reject.h>
  16
  17 static void nft_reject_inet_eval(const struct nft_expr *expr,
  18                                  struct nft_regs *regs,
  19                                  const struct nft_pktinfo *pkt)
  20 {
  21         struct nft_reject *priv = nft_expr_priv(expr);
  22
  23         switch (nft_pf(pkt)) {
  24         case NFPROTO_IPV4:
  25                 switch (priv->type) {
  26                 case NFT_REJECT_ICMP_UNREACH:
  27                         nf_send_unreach(pkt->skb, priv->icmp_code,
  28                                         nft_hook(pkt));
  29                         break;
  30                 case NFT_REJECT_TCP_RST:
  31                         nf_send_reset(nft_net(pkt), pkt->xt.state->sk,
  32                                       pkt->skb, nft_hook(pkt));
  33                         break;
  34                 case NFT_REJECT_ICMPX_UNREACH:
  35                         nf_send_unreach(pkt->skb,
  36                                         nft_reject_icmp_code(priv->icmp_code),
  37                                         nft_hook(pkt));
  38                         break;
  39                 }
  40                 break;
  41         case NFPROTO_IPV6:
  42                 switch (priv->type) {
  43                 case NFT_REJECT_ICMP_UNREACH:
  44                         nf_send_unreach6(nft_net(pkt), pkt->skb,
  45                                          priv->icmp_code, nft_hook(pkt));
  46                         break;
  47                 case NFT_REJECT_TCP_RST:
  48                         nf_send_reset6(nft_net(pkt), pkt->xt.state->sk,
  49                                        pkt->skb, nft_hook(pkt));
  50                         break;
  51                 case NFT_REJECT_ICMPX_UNREACH:
  52                         nf_send_unreach6(nft_net(pkt), pkt->skb,
  53                                          nft_reject_icmpv6_code(priv->icmp_code),
  54                                          nft_hook(pkt));
  55                         break;
  56                 }
  57                 break;
  58         }
  59
  60         regs->verdict.code = NF_DROP;
  61 }
  62
  63 static int nft_reject_inet_validate(const struct nft_ctx *ctx,
  64                                     const struct nft_expr *expr,
  65                                     const struct nft_data **data)
  66 {
  67         return nft_chain_validate_hooks(ctx->chain,
  68                                         (1 << NF_INET_LOCAL_IN) |
  69                                         (1 << NF_INET_FORWARD) |
  70                                         (1 << NF_INET_LOCAL_OUT) |
  71                                         (1 << NF_INET_PRE_ROUTING) |
  72                                         (1 << NF_INET_INGRESS));
  73 }
  74
  75 static struct nft_expr_type nft_reject_inet_type;
  76 static const struct nft_expr_ops nft_reject_inet_ops = {
  77         .type           = &nft_reject_inet_type,
  78         .size           = NFT_EXPR_SIZE(sizeof(struct nft_reject)),
  79         .eval           = nft_reject_inet_eval,
  80         .init           = nft_reject_init,
  81         .dump           = nft_reject_dump,
  82         .validate       = nft_reject_inet_validate,
  83 };
  84
  85 static struct nft_expr_type nft_reject_inet_type __read_mostly = {
  86         .family         = NFPROTO_INET,
  87         .name           = "reject",
  88         .ops            = &nft_reject_inet_ops,
  89         .policy         = nft_reject_policy,
  90         .maxattr        = NFTA_REJECT_MAX,
  91         .owner          = THIS_MODULE,
  92 };
  93
  94 static int __init nft_reject_inet_module_init(void)
  95 {
  96         return nft_register_expr(&nft_reject_inet_type);
  97 }
  98
  99 static void __exit nft_reject_inet_module_exit(void)
 100 {
 101         nft_unregister_expr(&nft_reject_inet_type);
 102 }
 103
 104 module_init(nft_reject_inet_module_init);
 105 module_exit(nft_reject_inet_module_exit);
 106
 107 MODULE_LICENSE("GPL");
 108 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 109 MODULE_ALIAS_NFT_AF_EXPR(1, "reject");
 110 MODULE_DESCRIPTION("Netfilter nftables reject inet support");