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 static unsigned int
  39 reject_tg6(struct sk_buff *skb, const struct xt_action_param *par)
  40 {
  41         const struct ip6t_reject_info *reject = par->targinfo;
  42         struct net *net = xt_net(par);
  43
  44         switch (reject->with) {
  45         case IP6T_ICMP6_NO_ROUTE:
  46                 nf_send_unreach6(net, skb, ICMPV6_NOROUTE, xt_hooknum(par));
  47                 break;
  48         case IP6T_ICMP6_ADM_PROHIBITED:
  49                 nf_send_unreach6(net, skb, ICMPV6_ADM_PROHIBITED,
  50                                  xt_hooknum(par));
  51                 break;
  52         case IP6T_ICMP6_NOT_NEIGHBOUR:
  53                 nf_send_unreach6(net, skb, ICMPV6_NOT_NEIGHBOUR,
  54                                  xt_hooknum(par));
  55                 break;
  56         case IP6T_ICMP6_ADDR_UNREACH:
  57                 nf_send_unreach6(net, skb, ICMPV6_ADDR_UNREACH,
  58                                  xt_hooknum(par));
  59                 break;
  60         case IP6T_ICMP6_PORT_UNREACH:
  61                 nf_send_unreach6(net, skb, ICMPV6_PORT_UNREACH,
  62                                  xt_hooknum(par));
  63                 break;
  64         case IP6T_ICMP6_ECHOREPLY:
  65                 /* Do nothing */
  66                 break;
  67         case IP6T_TCP_RESET:
  68                 nf_send_reset6(net, skb, xt_hooknum(par));
  69                 break;
  70         case IP6T_ICMP6_POLICY_FAIL:
  71                 nf_send_unreach6(net, skb, ICMPV6_POLICY_FAIL, xt_hooknum(par));
  72                 break;
  73         case IP6T_ICMP6_REJECT_ROUTE:
  74                 nf_send_unreach6(net, skb, ICMPV6_REJECT_ROUTE,
  75                                  xt_hooknum(par));
  76                 break;
  77         }
  78
  79         return NF_DROP;
  80 }
  81
  82 static int reject_tg6_check(const struct xt_tgchk_param *par)
  83 {
  84         const struct ip6t_reject_info *rejinfo = par->targinfo;
  85         const struct ip6t_entry *e = par->entryinfo;
  86
  87         if (rejinfo->with == IP6T_ICMP6_ECHOREPLY) {
  88                 pr_info("ECHOREPLY is not supported.\n");
  89                 return -EINVAL;
  90         } else if (rejinfo->with == IP6T_TCP_RESET) {
  91                 /* Must specify that it's a TCP packet */
  92                 if (!(e->ipv6.flags & IP6T_F_PROTO) ||
  93                     e->ipv6.proto != IPPROTO_TCP ||
  94                     (e->ipv6.invflags & XT_INV_PROTO)) {
  95                         pr_info("TCP_RESET illegal for non-tcp\n");
  96                         return -EINVAL;
  97                 }
  98         }
  99         return 0;
 100 }
 101
 102 static struct xt_target reject_tg6_reg __read_mostly = {
 103         .name           = "REJECT",
 104         .family         = NFPROTO_IPV6,
 105         .target         = reject_tg6,
 106         .targetsize     = sizeof(struct ip6t_reject_info),
 107         .table          = "filter",
 108         .hooks          = (1 << NF_INET_LOCAL_IN) | (1 << NF_INET_FORWARD) |
 109                           (1 << NF_INET_LOCAL_OUT),
 110         .checkentry     = reject_tg6_check,
 111         .me             = THIS_MODULE
 112 };
 113
 114 static int __init reject_tg6_init(void)
 115 {
 116         return xt_register_target(&reject_tg6_reg);
 117 }
 118
 119 static void __exit reject_tg6_exit(void)
 120 {
 121         xt_unregister_target(&reject_tg6_reg);
 122 }
 123
 124 module_init(reject_tg6_init);
 125 module_exit(reject_tg6_exit);