net/ipv6/netfilter/ip6t_REJECT.c

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