net/ipv6/netfilter/ip6t_REJECT.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * IP6 tables REJECT target module
   4  * Linux INET6 implementation
   5  *
   6  * Copyright (C)2003 USAGI/WIDE Project
   7  *
   8  * Authors:
   9  *      Yasuyuki Kozakai        <yasuyuki.kozakai@toshiba.co.jp>
  10  *
  11  * Copyright (c) 2005-2007 Patrick McHardy <kaber@trash.net>
  12  *
  13  * Based on net/ipv4/netfilter/ipt_REJECT.c
  14  */
  15 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  16
  17 #include <linux/gfp.h>
  18 #include <linux/module.h>
  19 #include <linux/skbuff.h>
  20 #include <linux/icmpv6.h>
  21 #include <linux/netdevice.h>
  22 #include <net/icmp.h>
  23 #include <net/flow.h>
  24 #include <linux/netfilter/x_tables.h>
  25 #include <linux/netfilter_ipv6/ip6_tables.h>
  26 #include <linux/netfilter_ipv6/ip6t_REJECT.h>
  27
  28 #include <net/netfilter/ipv6/nf_reject.h>
  29
  30 MODULE_AUTHOR("Yasuyuki KOZAKAI <yasuyuki.kozakai@toshiba.co.jp>");
  31 MODULE_DESCRIPTION("Xtables: packet \"rejection\" target for IPv6");
  32 MODULE_LICENSE("GPL");
  33
  34 static unsigned int
  35 reject_tg6(struct sk_buff *skb, const struct xt_action_param *par)
  36 {
  37         const struct ip6t_reject_info *reject = par->targinfo;
  38         struct net *net = xt_net(par);
  39
  40         switch (reject->with) {
  41         case IP6T_ICMP6_NO_ROUTE:
  42                 nf_send_unreach6(net, skb, ICMPV6_NOROUTE, xt_hooknum(par));
  43                 break;
  44         case IP6T_ICMP6_ADM_PROHIBITED:
  45                 nf_send_unreach6(net, skb, ICMPV6_ADM_PROHIBITED,
  46                                  xt_hooknum(par));
  47                 break;
  48         case IP6T_ICMP6_NOT_NEIGHBOUR:
  49                 nf_send_unreach6(net, skb, ICMPV6_NOT_NEIGHBOUR,
  50                                  xt_hooknum(par));
  51                 break;
  52         case IP6T_ICMP6_ADDR_UNREACH:
  53                 nf_send_unreach6(net, skb, ICMPV6_ADDR_UNREACH,
  54                                  xt_hooknum(par));
  55                 break;
  56         case IP6T_ICMP6_PORT_UNREACH:
  57                 nf_send_unreach6(net, skb, ICMPV6_PORT_UNREACH,
  58                                  xt_hooknum(par));
  59                 break;
  60         case IP6T_ICMP6_ECHOREPLY:
  61                 /* Do nothing */
  62                 break;
  63         case IP6T_TCP_RESET:
  64                 nf_send_reset6(net, par->state->sk, skb, xt_hooknum(par));
  65                 break;
  66         case IP6T_ICMP6_POLICY_FAIL:
  67                 nf_send_unreach6(net, skb, ICMPV6_POLICY_FAIL, xt_hooknum(par));
  68                 break;
  69         case IP6T_ICMP6_REJECT_ROUTE:
  70                 nf_send_unreach6(net, skb, ICMPV6_REJECT_ROUTE,
  71                                  xt_hooknum(par));
  72                 break;
  73         }
  74
  75         return NF_DROP;
  76 }
  77
  78 static int reject_tg6_check(const struct xt_tgchk_param *par)
  79 {
  80         const struct ip6t_reject_info *rejinfo = par->targinfo;
  81         const struct ip6t_entry *e = par->entryinfo;
  82
  83         if (rejinfo->with == IP6T_ICMP6_ECHOREPLY) {
  84                 pr_info_ratelimited("ECHOREPLY is not supported\n");
  85                 return -EINVAL;
  86         } else if (rejinfo->with == IP6T_TCP_RESET) {
  87                 /* Must specify that it's a TCP packet */
  88                 if (!(e->ipv6.flags & IP6T_F_PROTO) ||
  89                     e->ipv6.proto != IPPROTO_TCP ||
  90                     (e->ipv6.invflags & XT_INV_PROTO)) {
  91                         pr_info_ratelimited("TCP_RESET illegal for non-tcp\n");
  92                         return -EINVAL;
  93                 }
  94         }
  95         return 0;
  96 }
  97
  98 static struct xt_target reject_tg6_reg __read_mostly = {
  99         .name           = "REJECT",
 100         .family         = NFPROTO_IPV6,
 101         .target         = reject_tg6,
 102         .targetsize     = sizeof(struct ip6t_reject_info),
 103         .table          = "filter",
 104         .hooks          = (1 << NF_INET_LOCAL_IN) | (1 << NF_INET_FORWARD) |
 105                           (1 << NF_INET_LOCAL_OUT),
 106         .checkentry     = reject_tg6_check,
 107         .me             = THIS_MODULE
 108 };
 109
 110 static int __init reject_tg6_init(void)
 111 {
 112         return xt_register_target(&reject_tg6_reg);
 113 }
 114
 115 static void __exit reject_tg6_exit(void)
 116 {
 117         xt_unregister_target(&reject_tg6_reg);
 118 }
 119
 120 module_init(reject_tg6_init);
 121 module_exit(reject_tg6_exit);