LXR linux/net/ipv6/netfilter/ip6t

   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
  30MODULE_AUTHOR("Yasuyuki KOZAKAI <yasuyuki.kozakai@toshiba.co.jp>");
  31MODULE_DESCRIPTION("Xtables: packet \"rejection\" target for IPv6");
  32MODULE_LICENSE("GPL");
  33
  34static unsigned int
  35reject_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, 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
  78static 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
  98static 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
 110static int __init reject_tg6_init(void)
 111{
 112        return xt_register_target(&reject_tg6_reg);
 113}
 114
 115static void __exit reject_tg6_exit(void)
 116{
 117        xt_unregister_target(&reject_tg6_reg);
 118}
 119
 120module_init(reject_tg6_init);
 121module_exit(reject_tg6_exit);
 122