net/netfilter/nf_conntrack_proto_icmpv6.c - kernel/common - Git at Google

 /*
  * Copyright (C)2003,2004 USAGI/WIDE Project
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  * Author:
  *	Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
  */

 #include <linux/types.h>
 #include <linux/timer.h>
 #include <linux/module.h>
 #include <linux/netfilter.h>
 #include <linux/in6.h>
 #include <linux/icmpv6.h>
 #include <linux/ipv6.h>
 #include <net/ipv6.h>
 #include <net/ip6_checksum.h>
 #include <linux/seq_file.h>
 #include <linux/netfilter_ipv6.h>
 #include <net/netfilter/nf_conntrack_tuple.h>
 #include <net/netfilter/nf_conntrack_l4proto.h>
 #include <net/netfilter/nf_conntrack_core.h>
 #include <net/netfilter/nf_conntrack_timeout.h>
 #include <net/netfilter/nf_conntrack_zones.h>
 #include <net/netfilter/ipv6/nf_conntrack_icmpv6.h>
 #include <net/netfilter/nf_log.h>

 static const unsigned int nf_ct_icmpv6_timeout = 30*HZ;

 static inline struct nf_icmp_net *icmpv6_pernet(struct net *net)
 {
 	return &net->ct.nf_ct_proto.icmpv6;
 }

 static bool icmpv6_pkt_to_tuple(const struct sk_buff *skb,
 				unsigned int dataoff,
 				struct net *net,
 				struct nf_conntrack_tuple *tuple)
 {
 	const struct icmp6hdr *hp;
 	struct icmp6hdr _hdr;

 	hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
 	if (hp == NULL)
 		return false;
 	tuple->dst.u.icmp.type = hp->icmp6_type;
 	tuple->src.u.icmp.id = hp->icmp6_identifier;
 	tuple->dst.u.icmp.code = hp->icmp6_code;

 	return true;
 }

 /* Add 1; spaces filled with 0. */
 static const u_int8_t invmap[] = {
 	[ICMPV6_ECHO_REQUEST - 128]	= ICMPV6_ECHO_REPLY + 1,
 	[ICMPV6_ECHO_REPLY - 128]	= ICMPV6_ECHO_REQUEST + 1,
 	[ICMPV6_NI_QUERY - 128]		= ICMPV6_NI_REPLY + 1,
 	[ICMPV6_NI_REPLY - 128]		= ICMPV6_NI_QUERY + 1
 };

 static const u_int8_t noct_valid_new[] = {
 	[ICMPV6_MGM_QUERY - 130] = 1,
 	[ICMPV6_MGM_REPORT - 130] = 1,
 	[ICMPV6_MGM_REDUCTION - 130] = 1,
 	[NDISC_ROUTER_SOLICITATION - 130] = 1,
 	[NDISC_ROUTER_ADVERTISEMENT - 130] = 1,
 	[NDISC_NEIGHBOUR_SOLICITATION - 130] = 1,
 	[NDISC_NEIGHBOUR_ADVERTISEMENT - 130] = 1,
 	[ICMPV6_MLD2_REPORT - 130] = 1
 };

 static bool icmpv6_invert_tuple(struct nf_conntrack_tuple *tuple,
 				const struct nf_conntrack_tuple *orig)
 {
 	int type = orig->dst.u.icmp.type - 128;
 	if (type < 0 || type >= sizeof(invmap) || !invmap[type])
 		return false;

 	tuple->src.u.icmp.id   = orig->src.u.icmp.id;
 	tuple->dst.u.icmp.type = invmap[type] - 1;
 	tuple->dst.u.icmp.code = orig->dst.u.icmp.code;
 	return true;
 }

 static unsigned int *icmpv6_get_timeouts(struct net *net)
 {
 	return &icmpv6_pernet(net)->timeout;
 }

 /* Returns verdict for packet, or -1 for invalid. */
 static int icmpv6_packet(struct nf_conn *ct,
 		       const struct sk_buff *skb,
 		       unsigned int dataoff,
 		       enum ip_conntrack_info ctinfo)
 {
 	unsigned int *timeout = nf_ct_timeout_lookup(ct);

 	if (!timeout)
 		timeout = icmpv6_get_timeouts(nf_ct_net(ct));

 	/* Do not immediately delete the connection after the first
 	   successful reply to avoid excessive conntrackd traffic
 	   and also to handle correctly ICMP echo reply duplicates. */
 	nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);

 	return NF_ACCEPT;
 }

 /* Called when a new connection for this protocol found. */
 static bool icmpv6_new(struct nf_conn *ct, const struct sk_buff *skb,
 		       unsigned int dataoff)
 {
 	static const u_int8_t valid_new[] = {
 		[ICMPV6_ECHO_REQUEST - 128] = 1,
 		[ICMPV6_NI_QUERY - 128] = 1
 	};
 	int type = ct->tuplehash[0].tuple.dst.u.icmp.type - 128;

 	if (type < 0 || type >= sizeof(valid_new) || !valid_new[type]) {
 		/* Can't create a new ICMPv6 `conn' with this. */
 		pr_debug("icmpv6: can't create new conn with type %u\n",
 			 type + 128);
 		nf_ct_dump_tuple_ipv6(&ct->tuplehash[0].tuple);
 		return false;
 	}
 	return true;
 }

 static int
 icmpv6_error_message(struct net *net, struct nf_conn *tmpl,
 		     struct sk_buff *skb,
 		     unsigned int icmp6off)
 {
 	struct nf_conntrack_tuple intuple, origtuple;
 	const struct nf_conntrack_tuple_hash *h;
 	const struct nf_conntrack_l4proto *inproto;
 	enum ip_conntrack_info ctinfo;
 	struct nf_conntrack_zone tmp;

 	WARN_ON(skb_nfct(skb));

 	/* Are they talking about one of our connections? */
 	if (!nf_ct_get_tuplepr(skb,
 			       skb_network_offset(skb)
 				+ sizeof(struct ipv6hdr)
 				+ sizeof(struct icmp6hdr),
 			       PF_INET6, net, &origtuple)) {
 		pr_debug("icmpv6_error: Can't get tuple\n");
 		return -NF_ACCEPT;
 	}

 	/* rcu_read_lock()ed by nf_hook_thresh */
 	inproto = __nf_ct_l4proto_find(PF_INET6, origtuple.dst.protonum);

 	/* Ordinarily, we'd expect the inverted tupleproto, but it's
 	   been preserved inside the ICMP. */
 	if (!nf_ct_invert_tuple(&intuple, &origtuple, inproto)) {
 		pr_debug("icmpv6_error: Can't invert tuple\n");
 		return -NF_ACCEPT;
 	}

 	ctinfo = IP_CT_RELATED;

 	h = nf_conntrack_find_get(net, nf_ct_zone_tmpl(tmpl, skb, &tmp),
 				  &intuple);
 	if (!h) {
 		pr_debug("icmpv6_error: no match\n");
 		return -NF_ACCEPT;
 	} else {
 		if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY)
 			ctinfo += IP_CT_IS_REPLY;
 	}

 	/* Update skb to refer to this connection */
 	nf_ct_set(skb, nf_ct_tuplehash_to_ctrack(h), ctinfo);
 	return NF_ACCEPT;
 }

 static void icmpv6_error_log(const struct sk_buff *skb, struct net *net,
 			     u8 pf, const char *msg)
 {
 	nf_l4proto_log_invalid(skb, net, pf, IPPROTO_ICMPV6, "%s", msg);
 }

 static int
 icmpv6_error(struct net *net, struct nf_conn *tmpl,
 	     struct sk_buff *skb, unsigned int dataoff,
 	     u8 pf, unsigned int hooknum)
 {
 	const struct icmp6hdr *icmp6h;
 	struct icmp6hdr _ih;
 	int type;

 	icmp6h = skb_header_pointer(skb, dataoff, sizeof(_ih), &_ih);
 	if (icmp6h == NULL) {
 		icmpv6_error_log(skb, net, pf, "short packet");
 		return -NF_ACCEPT;
 	}

 	if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
 	    nf_ip6_checksum(skb, hooknum, dataoff, IPPROTO_ICMPV6)) {
 		icmpv6_error_log(skb, net, pf, "ICMPv6 checksum failed");
 		return -NF_ACCEPT;
 	}

 	type = icmp6h->icmp6_type - 130;
 	if (type >= 0 && type < sizeof(noct_valid_new) &&
 	    noct_valid_new[type]) {
 		nf_ct_set(skb, NULL, IP_CT_UNTRACKED);
 		return NF_ACCEPT;
 	}

 	/* is not error message ? */
 	if (icmp6h->icmp6_type >= 128)
 		return NF_ACCEPT;

 	return icmpv6_error_message(net, tmpl, skb, dataoff);
 }

 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)

 #include <linux/netfilter/nfnetlink.h>
 #include <linux/netfilter/nfnetlink_conntrack.h>
 static int icmpv6_tuple_to_nlattr(struct sk_buff *skb,
 				  const struct nf_conntrack_tuple *t)
 {
 	if (nla_put_be16(skb, CTA_PROTO_ICMPV6_ID, t->src.u.icmp.id) ||
 	    nla_put_u8(skb, CTA_PROTO_ICMPV6_TYPE, t->dst.u.icmp.type) ||
 	    nla_put_u8(skb, CTA_PROTO_ICMPV6_CODE, t->dst.u.icmp.code))
 		goto nla_put_failure;
 	return 0;

 nla_put_failure:
 	return -1;
 }

 static const struct nla_policy icmpv6_nla_policy[CTA_PROTO_MAX+1] = {
 	[CTA_PROTO_ICMPV6_TYPE]	= { .type = NLA_U8 },
 	[CTA_PROTO_ICMPV6_CODE]	= { .type = NLA_U8 },
 	[CTA_PROTO_ICMPV6_ID]	= { .type = NLA_U16 },
 };

 static int icmpv6_nlattr_to_tuple(struct nlattr *tb[],
 				struct nf_conntrack_tuple *tuple)
 {
 	if (!tb[CTA_PROTO_ICMPV6_TYPE] ||
 	    !tb[CTA_PROTO_ICMPV6_CODE] ||
 	    !tb[CTA_PROTO_ICMPV6_ID])
 		return -EINVAL;

 	tuple->dst.u.icmp.type = nla_get_u8(tb[CTA_PROTO_ICMPV6_TYPE]);
 	tuple->dst.u.icmp.code = nla_get_u8(tb[CTA_PROTO_ICMPV6_CODE]);
 	tuple->src.u.icmp.id = nla_get_be16(tb[CTA_PROTO_ICMPV6_ID]);

 	if (tuple->dst.u.icmp.type < 128 ||
 	    tuple->dst.u.icmp.type - 128 >= sizeof(invmap) ||
 	    !invmap[tuple->dst.u.icmp.type - 128])
 		return -EINVAL;

 	return 0;
 }

 static unsigned int icmpv6_nlattr_tuple_size(void)
 {
 	static unsigned int size __read_mostly;

 	if (!size)
 		size = nla_policy_len(icmpv6_nla_policy, CTA_PROTO_MAX + 1);

 	return size;
 }
 #endif

 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT

 #include <linux/netfilter/nfnetlink.h>
 #include <linux/netfilter/nfnetlink_cttimeout.h>

 static int icmpv6_timeout_nlattr_to_obj(struct nlattr *tb[],
 					struct net *net, void *data)
 {
 	unsigned int *timeout = data;
 	struct nf_icmp_net *in = icmpv6_pernet(net);

 	if (!timeout)
 		timeout = icmpv6_get_timeouts(net);
 	if (tb[CTA_TIMEOUT_ICMPV6_TIMEOUT]) {
 		*timeout =
 		    ntohl(nla_get_be32(tb[CTA_TIMEOUT_ICMPV6_TIMEOUT])) * HZ;
 	} else {
 		/* Set default ICMPv6 timeout. */
 		*timeout = in->timeout;
 	}
 	return 0;
 }

 static int
 icmpv6_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
 {
 	const unsigned int *timeout = data;

 	if (nla_put_be32(skb, CTA_TIMEOUT_ICMPV6_TIMEOUT, htonl(*timeout / HZ)))
 		goto nla_put_failure;
 	return 0;

 nla_put_failure:
 	return -ENOSPC;
 }

 static const struct nla_policy
 icmpv6_timeout_nla_policy[CTA_TIMEOUT_ICMPV6_MAX+1] = {
 	[CTA_TIMEOUT_ICMPV6_TIMEOUT]	= { .type = NLA_U32 },
 };
 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */

 #ifdef CONFIG_SYSCTL
 static struct ctl_table icmpv6_sysctl_table[] = {
 	{
 		.procname	= "nf_conntrack_icmpv6_timeout",
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_jiffies,
 	},
 	{ }
 };
 #endif /* CONFIG_SYSCTL */

 static int icmpv6_kmemdup_sysctl_table(struct nf_proto_net *pn,
 				       struct nf_icmp_net *in)
 {
 #ifdef CONFIG_SYSCTL
 	pn->ctl_table = kmemdup(icmpv6_sysctl_table,
 				sizeof(icmpv6_sysctl_table),
 				GFP_KERNEL);
 	if (!pn->ctl_table)
 		return -ENOMEM;

 	pn->ctl_table[0].data = &in->timeout;
 #endif
 	return 0;
 }

 static int icmpv6_init_net(struct net *net, u_int16_t proto)
 {
 	struct nf_icmp_net *in = icmpv6_pernet(net);
 	struct nf_proto_net *pn = &in->pn;

 	in->timeout = nf_ct_icmpv6_timeout;

 	return icmpv6_kmemdup_sysctl_table(pn, in);
 }

 static struct nf_proto_net *icmpv6_get_net_proto(struct net *net)
 {
 	return &net->ct.nf_ct_proto.icmpv6.pn;
 }

 const struct nf_conntrack_l4proto nf_conntrack_l4proto_icmpv6 =
 {
 	.l3proto		= PF_INET6,
 	.l4proto		= IPPROTO_ICMPV6,
 	.pkt_to_tuple		= icmpv6_pkt_to_tuple,
 	.invert_tuple		= icmpv6_invert_tuple,
 	.packet			= icmpv6_packet,
 	.new			= icmpv6_new,
 	.error			= icmpv6_error,
 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
 	.tuple_to_nlattr	= icmpv6_tuple_to_nlattr,
 	.nlattr_tuple_size	= icmpv6_nlattr_tuple_size,
 	.nlattr_to_tuple	= icmpv6_nlattr_to_tuple,
 	.nla_policy		= icmpv6_nla_policy,
 #endif
 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
 	.ctnl_timeout		= {
 		.nlattr_to_obj	= icmpv6_timeout_nlattr_to_obj,
 		.obj_to_nlattr	= icmpv6_timeout_obj_to_nlattr,
 		.nlattr_max	= CTA_TIMEOUT_ICMP_MAX,
 		.obj_size	= sizeof(unsigned int),
 		.nla_policy	= icmpv6_timeout_nla_policy,
 	},
 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
 	.init_net		= icmpv6_init_net,
 	.get_net_proto		= icmpv6_get_net_proto,
 };
	/*
	* Copyright (C)2003,2004 USAGI/WIDE Project
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	* Author:
	* Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
	*/

	#include <linux/types.h>
	#include <linux/timer.h>
	#include <linux/module.h>
	#include <linux/netfilter.h>
	#include <linux/in6.h>
	#include <linux/icmpv6.h>
	#include <linux/ipv6.h>
	#include <net/ipv6.h>
	#include <net/ip6_checksum.h>
	#include <linux/seq_file.h>
	#include <linux/netfilter_ipv6.h>
	#include <net/netfilter/nf_conntrack_tuple.h>
	#include <net/netfilter/nf_conntrack_l4proto.h>
	#include <net/netfilter/nf_conntrack_core.h>
	#include <net/netfilter/nf_conntrack_timeout.h>
	#include <net/netfilter/nf_conntrack_zones.h>
	#include <net/netfilter/ipv6/nf_conntrack_icmpv6.h>
	#include <net/netfilter/nf_log.h>

	static const unsigned int nf_ct_icmpv6_timeout = 30*HZ;

	static inline struct nf_icmp_net icmpv6_pernet(struct net net)
	{
	return &net->ct.nf_ct_proto.icmpv6;
	}

	static bool icmpv6_pkt_to_tuple(const struct sk_buff *skb,
	unsigned int dataoff,
	struct net *net,
	struct nf_conntrack_tuple *tuple)
	{
	const struct icmp6hdr *hp;
	struct icmp6hdr _hdr;

	hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
	if (hp == NULL)
	return false;
	tuple->dst.u.icmp.type = hp->icmp6_type;
	tuple->src.u.icmp.id = hp->icmp6_identifier;
	tuple->dst.u.icmp.code = hp->icmp6_code;

	return true;
	}

	/* Add 1; spaces filled with 0. */
	static const u_int8_t invmap[] = {
	[ICMPV6_ECHO_REQUEST - 128] = ICMPV6_ECHO_REPLY + 1,
	[ICMPV6_ECHO_REPLY - 128] = ICMPV6_ECHO_REQUEST + 1,
	[ICMPV6_NI_QUERY - 128] = ICMPV6_NI_REPLY + 1,
	[ICMPV6_NI_REPLY - 128] = ICMPV6_NI_QUERY + 1
	};

	static const u_int8_t noct_valid_new[] = {
	[ICMPV6_MGM_QUERY - 130] = 1,
	[ICMPV6_MGM_REPORT - 130] = 1,
	[ICMPV6_MGM_REDUCTION - 130] = 1,
	[NDISC_ROUTER_SOLICITATION - 130] = 1,
	[NDISC_ROUTER_ADVERTISEMENT - 130] = 1,
	[NDISC_NEIGHBOUR_SOLICITATION - 130] = 1,
	[NDISC_NEIGHBOUR_ADVERTISEMENT - 130] = 1,
	[ICMPV6_MLD2_REPORT - 130] = 1
	};

	static bool icmpv6_invert_tuple(struct nf_conntrack_tuple *tuple,
	const struct nf_conntrack_tuple *orig)
	{
	int type = orig->dst.u.icmp.type - 128;
	if (type < 0 \|\| type >= sizeof(invmap) \|\| !invmap[type])
	return false;

	tuple->src.u.icmp.id = orig->src.u.icmp.id;
	tuple->dst.u.icmp.type = invmap[type] - 1;
	tuple->dst.u.icmp.code = orig->dst.u.icmp.code;
	return true;
	}

	static unsigned int icmpv6_get_timeouts(struct net net)
	{
	return &icmpv6_pernet(net)->timeout;
	}

	/* Returns verdict for packet, or -1 for invalid. */
	static int icmpv6_packet(struct nf_conn *ct,
	const struct sk_buff *skb,
	unsigned int dataoff,
	enum ip_conntrack_info ctinfo)
	{
	unsigned int *timeout = nf_ct_timeout_lookup(ct);

	if (!timeout)
	timeout = icmpv6_get_timeouts(nf_ct_net(ct));

	/* Do not immediately delete the connection after the first
	successful reply to avoid excessive conntrackd traffic
	and also to handle correctly ICMP echo reply duplicates. */
	nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);

	return NF_ACCEPT;
	}

	/* Called when a new connection for this protocol found. */
	static bool icmpv6_new(struct nf_conn ct, const struct sk_buff skb,
	unsigned int dataoff)
	{
	static const u_int8_t valid_new[] = {
	[ICMPV6_ECHO_REQUEST - 128] = 1,
	[ICMPV6_NI_QUERY - 128] = 1
	};
	int type = ct->tuplehash[0].tuple.dst.u.icmp.type - 128;

	if (type < 0 \|\| type >= sizeof(valid_new) \|\| !valid_new[type]) {
	/* Can't create a new ICMPv6 `conn' with this. */
	pr_debug("icmpv6: can't create new conn with type %u\n",
	type + 128);
	nf_ct_dump_tuple_ipv6(&ct->tuplehash[0].tuple);
	return false;
	}
	return true;
	}

	static int
	icmpv6_error_message(struct net net, struct nf_conn tmpl,
	struct sk_buff *skb,
	unsigned int icmp6off)
	{
	struct nf_conntrack_tuple intuple, origtuple;
	const struct nf_conntrack_tuple_hash *h;
	const struct nf_conntrack_l4proto *inproto;
	enum ip_conntrack_info ctinfo;
	struct nf_conntrack_zone tmp;

	WARN_ON(skb_nfct(skb));

	/* Are they talking about one of our connections? */
	if (!nf_ct_get_tuplepr(skb,
	skb_network_offset(skb)
	+ sizeof(struct ipv6hdr)
	+ sizeof(struct icmp6hdr),
	PF_INET6, net, &origtuple)) {
	pr_debug("icmpv6_error: Can't get tuple\n");
	return -NF_ACCEPT;
	}

	/* rcu_read_lock()ed by nf_hook_thresh */
	inproto = __nf_ct_l4proto_find(PF_INET6, origtuple.dst.protonum);

	/* Ordinarily, we'd expect the inverted tupleproto, but it's
	been preserved inside the ICMP. */
	if (!nf_ct_invert_tuple(&intuple, &origtuple, inproto)) {
	pr_debug("icmpv6_error: Can't invert tuple\n");
	return -NF_ACCEPT;
	}

	ctinfo = IP_CT_RELATED;

	h = nf_conntrack_find_get(net, nf_ct_zone_tmpl(tmpl, skb, &tmp),
	&intuple);
	if (!h) {
	pr_debug("icmpv6_error: no match\n");
	return -NF_ACCEPT;
	} else {
	if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY)
	ctinfo += IP_CT_IS_REPLY;
	}

	/* Update skb to refer to this connection */
	nf_ct_set(skb, nf_ct_tuplehash_to_ctrack(h), ctinfo);
	return NF_ACCEPT;
	}

	static void icmpv6_error_log(const struct sk_buff skb, struct net net,
	u8 pf, const char *msg)
	{
	nf_l4proto_log_invalid(skb, net, pf, IPPROTO_ICMPV6, "%s", msg);
	}

	static int
	icmpv6_error(struct net net, struct nf_conn tmpl,
	struct sk_buff *skb, unsigned int dataoff,
	u8 pf, unsigned int hooknum)
	{
	const struct icmp6hdr *icmp6h;
	struct icmp6hdr _ih;
	int type;

	icmp6h = skb_header_pointer(skb, dataoff, sizeof(_ih), &_ih);
	if (icmp6h == NULL) {
	icmpv6_error_log(skb, net, pf, "short packet");
	return -NF_ACCEPT;
	}

	if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
	nf_ip6_checksum(skb, hooknum, dataoff, IPPROTO_ICMPV6)) {
	icmpv6_error_log(skb, net, pf, "ICMPv6 checksum failed");
	return -NF_ACCEPT;
	}

	type = icmp6h->icmp6_type - 130;
	if (type >= 0 && type < sizeof(noct_valid_new) &&
	noct_valid_new[type]) {
	nf_ct_set(skb, NULL, IP_CT_UNTRACKED);
	return NF_ACCEPT;
	}

	/* is not error message ? */
	if (icmp6h->icmp6_type >= 128)
	return NF_ACCEPT;

	return icmpv6_error_message(net, tmpl, skb, dataoff);
	}

	#if IS_ENABLED(CONFIG_NF_CT_NETLINK)

	#include <linux/netfilter/nfnetlink.h>
	#include <linux/netfilter/nfnetlink_conntrack.h>
	static int icmpv6_tuple_to_nlattr(struct sk_buff *skb,
	const struct nf_conntrack_tuple *t)
	{
	if (nla_put_be16(skb, CTA_PROTO_ICMPV6_ID, t->src.u.icmp.id) \|\|
	nla_put_u8(skb, CTA_PROTO_ICMPV6_TYPE, t->dst.u.icmp.type) \|\|
	nla_put_u8(skb, CTA_PROTO_ICMPV6_CODE, t->dst.u.icmp.code))
	goto nla_put_failure;
	return 0;

	nla_put_failure:
	return -1;
	}

	static const struct nla_policy icmpv6_nla_policy[CTA_PROTO_MAX+1] = {
	[CTA_PROTO_ICMPV6_TYPE] = { .type = NLA_U8 },
	[CTA_PROTO_ICMPV6_CODE] = { .type = NLA_U8 },
	[CTA_PROTO_ICMPV6_ID] = { .type = NLA_U16 },
	};

	static int icmpv6_nlattr_to_tuple(struct nlattr *tb[],
	struct nf_conntrack_tuple *tuple)
	{
	if (!tb[CTA_PROTO_ICMPV6_TYPE] \|\|
	!tb[CTA_PROTO_ICMPV6_CODE] \|\|
	!tb[CTA_PROTO_ICMPV6_ID])
	return -EINVAL;

	tuple->dst.u.icmp.type = nla_get_u8(tb[CTA_PROTO_ICMPV6_TYPE]);
	tuple->dst.u.icmp.code = nla_get_u8(tb[CTA_PROTO_ICMPV6_CODE]);
	tuple->src.u.icmp.id = nla_get_be16(tb[CTA_PROTO_ICMPV6_ID]);

	if (tuple->dst.u.icmp.type < 128 \|\|
	tuple->dst.u.icmp.type - 128 >= sizeof(invmap) \|\|
	!invmap[tuple->dst.u.icmp.type - 128])
	return -EINVAL;

	return 0;
	}

	static unsigned int icmpv6_nlattr_tuple_size(void)
	{
	static unsigned int size __read_mostly;

	if (!size)
	size = nla_policy_len(icmpv6_nla_policy, CTA_PROTO_MAX + 1);

	return size;
	}
	#endif

	#ifdef CONFIG_NF_CONNTRACK_TIMEOUT

	#include <linux/netfilter/nfnetlink.h>
	#include <linux/netfilter/nfnetlink_cttimeout.h>

	static int icmpv6_timeout_nlattr_to_obj(struct nlattr *tb[],
	struct net net, void data)
	{
	unsigned int *timeout = data;
	struct nf_icmp_net *in = icmpv6_pernet(net);

	if (!timeout)
	timeout = icmpv6_get_timeouts(net);
	if (tb[CTA_TIMEOUT_ICMPV6_TIMEOUT]) {
	*timeout =
	ntohl(nla_get_be32(tb[CTA_TIMEOUT_ICMPV6_TIMEOUT])) * HZ;
	} else {
	/* Set default ICMPv6 timeout. */
	*timeout = in->timeout;
	}
	return 0;
	}

	static int
	icmpv6_timeout_obj_to_nlattr(struct sk_buff skb, const void data)
	{
	const unsigned int *timeout = data;

	if (nla_put_be32(skb, CTA_TIMEOUT_ICMPV6_TIMEOUT, htonl(*timeout / HZ)))
	goto nla_put_failure;
	return 0;

	nla_put_failure:
	return -ENOSPC;
	}

	static const struct nla_policy
	icmpv6_timeout_nla_policy[CTA_TIMEOUT_ICMPV6_MAX+1] = {
	[CTA_TIMEOUT_ICMPV6_TIMEOUT] = { .type = NLA_U32 },
	};
	#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */

	#ifdef CONFIG_SYSCTL
	static struct ctl_table icmpv6_sysctl_table[] = {
	{
	.procname = "nf_conntrack_icmpv6_timeout",
	.maxlen = sizeof(unsigned int),
	.mode = 0644,
	.proc_handler = proc_dointvec_jiffies,
	},
	{ }
	};
	#endif /* CONFIG_SYSCTL */

	static int icmpv6_kmemdup_sysctl_table(struct nf_proto_net *pn,
	struct nf_icmp_net *in)
	{
	#ifdef CONFIG_SYSCTL
	pn->ctl_table = kmemdup(icmpv6_sysctl_table,
	sizeof(icmpv6_sysctl_table),
	GFP_KERNEL);
	if (!pn->ctl_table)
	return -ENOMEM;

	pn->ctl_table[0].data = &in->timeout;
	#endif
	return 0;
	}

	static int icmpv6_init_net(struct net *net, u_int16_t proto)
	{
	struct nf_icmp_net *in = icmpv6_pernet(net);
	struct nf_proto_net *pn = &in->pn;

	in->timeout = nf_ct_icmpv6_timeout;

	return icmpv6_kmemdup_sysctl_table(pn, in);
	}

	static struct nf_proto_net icmpv6_get_net_proto(struct net net)
	{
	return &net->ct.nf_ct_proto.icmpv6.pn;
	}

	const struct nf_conntrack_l4proto nf_conntrack_l4proto_icmpv6 =
	{
	.l3proto = PF_INET6,
	.l4proto = IPPROTO_ICMPV6,
	.pkt_to_tuple = icmpv6_pkt_to_tuple,
	.invert_tuple = icmpv6_invert_tuple,
	.packet = icmpv6_packet,
	.new = icmpv6_new,
	.error = icmpv6_error,
	#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
	.tuple_to_nlattr = icmpv6_tuple_to_nlattr,
	.nlattr_tuple_size = icmpv6_nlattr_tuple_size,
	.nlattr_to_tuple = icmpv6_nlattr_to_tuple,
	.nla_policy = icmpv6_nla_policy,
	#endif
	#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
	.ctnl_timeout = {
	.nlattr_to_obj = icmpv6_timeout_nlattr_to_obj,
	.obj_to_nlattr = icmpv6_timeout_obj_to_nlattr,
	.nlattr_max = CTA_TIMEOUT_ICMP_MAX,
	.obj_size = sizeof(unsigned int),
	.nla_policy = icmpv6_timeout_nla_policy,
	},
	#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
	.init_net = icmpv6_init_net,
	.get_net_proto = icmpv6_get_net_proto,
	};