| 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, 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); |