LXR linux/net/ipv6/netfilter/ip6t

   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
  34MODULE_AUTHOR("Yasuyuki KOZAKAI <yasuyuki.kozakai@toshiba.co.jp>");
  35MODULE_DESCRIPTION("Xtables: packet \"rejection\" target for IPv6");
  36MODULE_LICENSE("GPL");
  37
  38static unsigned int
  39reject_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 = par->net;
  43
  44        switch (reject->with) {
  45        case IP6T_ICMP6_NO_ROUTE:
  46                nf_send_unreach6(net, skb, ICMPV6_NOROUTE, par->hooknum);
  47                break;
  48        case IP6T_ICMP6_ADM_PROHIBITED:
  49                nf_send_unreach6(net, skb, ICMPV6_ADM_PROHIBITED, par->hooknum);
  50                break;
  51        case IP6T_ICMP6_NOT_NEIGHBOUR:
  52                nf_send_unreach6(net, skb, ICMPV6_NOT_NEIGHBOUR, par->hooknum);
  53                break;
  54        case IP6T_ICMP6_ADDR_UNREACH:
  55                nf_send_unreach6(net, skb, ICMPV6_ADDR_UNREACH, par->hooknum);
  56                break;
  57        case IP6T_ICMP6_PORT_UNREACH:
  58                nf_send_unreach6(net, skb, ICMPV6_PORT_UNREACH, par->hooknum);
  59                break;
  60        case IP6T_ICMP6_ECHOREPLY:
  61                /* Do nothing */
  62                break;
  63        case IP6T_TCP_RESET:
  64                nf_send_reset6(net, skb, par->hooknum);
  65                break;
  66        case IP6T_ICMP6_POLICY_FAIL:
  67                nf_send_unreach6(net, skb, ICMPV6_POLICY_FAIL, par->hooknum);
  68                break;
  69        case IP6T_ICMP6_REJECT_ROUTE:
  70                nf_send_unreach6(net, skb, ICMPV6_REJECT_ROUTE, par->hooknum);
  71                break;
  72        }
  73
  74        return NF_DROP;
  75}
  76
  77static int reject_tg6_check(const struct xt_tgchk_param *par)
  78{
  79        const struct ip6t_reject_info *rejinfo = par->targinfo;
  80        const struct ip6t_entry *e = par->entryinfo;
  81
  82        if (rejinfo->with == IP6T_ICMP6_ECHOREPLY) {
  83                pr_info("ECHOREPLY is not supported.\n");
  84                return -EINVAL;
  85        } else if (rejinfo->with == IP6T_TCP_RESET) {
  86                /* Must specify that it's a TCP packet */
  87                if (!(e->ipv6.flags & IP6T_F_PROTO) ||
  88                    e->ipv6.proto != IPPROTO_TCP ||
  89                    (e->ipv6.invflags & XT_INV_PROTO)) {
  90                        pr_info("TCP_RESET illegal for non-tcp\n");
  91                        return -EINVAL;
  92                }
  93        }
  94        return 0;
  95}
  96
  97static struct xt_target reject_tg6_reg __read_mostly = {
  98        .name           = "REJECT",
  99        .family         = NFPROTO_IPV6,
 100        .target         = reject_tg6,
 101        .targetsize     = sizeof(struct ip6t_reject_info),
 102        .table          = "filter",
 103        .hooks          = (1 << NF_INET_LOCAL_IN) | (1 << NF_INET_FORWARD) |
 104                          (1 << NF_INET_LOCAL_OUT),
 105        .checkentry     = reject_tg6_check,
 106        .me             = THIS_MODULE
 107};
 108
 109static int __init reject_tg6_init(void)
 110{
 111        return xt_register_target(&reject_tg6_reg);
 112}
 113
 114static void __exit reject_tg6_exit(void)
 115{
 116        xt_unregister_target(&reject_tg6_reg);
 117}
 118
 119module_init(reject_tg6_init);
 120module_exit(reject_tg6_exit);
 121