[linux-2.6-block.git] / net / ipv6 / netfilter / nf_nat_l3proto_ipv6.c

/*
 * Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
 *
 * 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.
 *
 * Development of IPv6 NAT funded by Astaro.
 */
#include <linux/types.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/ipv6.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv6.h>
#include <net/secure_seq.h>
#include <net/checksum.h>
#include <net/ip6_checksum.h>
#include <net/ip6_route.h>
#include <net/ipv6.h>

#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_nat_core.h>
#include <net/netfilter/nf_nat_l3proto.h>
#include <net/netfilter/nf_nat_l4proto.h>

static const struct nf_nat_l3proto nf_nat_l3proto_ipv6;

#ifdef CONFIG_XFRM
static void nf_nat_ipv6_decode_session(struct sk_buff *skb,
				       const struct nf_conn *ct,
				       enum ip_conntrack_dir dir,
				       unsigned long statusbit,
				       struct flowi *fl)
{
	const struct nf_conntrack_tuple *t = &ct->tuplehash[dir].tuple;
	struct flowi6 *fl6 = &fl->u.ip6;

	if (ct->status & statusbit) {
		fl6->daddr = t->dst.u3.in6;
		if (t->dst.protonum == IPPROTO_TCP ||
		    t->dst.protonum == IPPROTO_UDP ||
		    t->dst.protonum == IPPROTO_UDPLITE ||
		    t->dst.protonum == IPPROTO_DCCP ||
		    t->dst.protonum == IPPROTO_SCTP)
			fl6->fl6_dport = t->dst.u.all;
	}

	statusbit ^= IPS_NAT_MASK;

	if (ct->status & statusbit) {
		fl6->saddr = t->src.u3.in6;
		if (t->dst.protonum == IPPROTO_TCP ||
		    t->dst.protonum == IPPROTO_UDP ||
		    t->dst.protonum == IPPROTO_UDPLITE ||
		    t->dst.protonum == IPPROTO_DCCP ||
		    t->dst.protonum == IPPROTO_SCTP)
			fl6->fl6_sport = t->src.u.all;
	}
}
#endif

static bool nf_nat_ipv6_in_range(const struct nf_conntrack_tuple *t,
				 const struct nf_nat_range *range)
{
	return ipv6_addr_cmp(&t->src.u3.in6, &range->min_addr.in6) >= 0 &&
	       ipv6_addr_cmp(&t->src.u3.in6, &range->max_addr.in6) <= 0;
}

static u32 nf_nat_ipv6_secure_port(const struct nf_conntrack_tuple *t,
				   __be16 dport)
{
	return secure_ipv6_port_ephemeral(t->src.u3.ip6, t->dst.u3.ip6, dport);
}

static bool nf_nat_ipv6_manip_pkt(struct sk_buff *skb,
				  unsigned int iphdroff,
				  const struct nf_nat_l4proto *l4proto,
				  const struct nf_conntrack_tuple *target,
				  enum nf_nat_manip_type maniptype)
{
	struct ipv6hdr *ipv6h;
	__be16 frag_off;
	int hdroff;
	u8 nexthdr;

	if (!skb_make_writable(skb, iphdroff + sizeof(*ipv6h)))
		return false;

	ipv6h = (void *)skb->data + iphdroff;
	nexthdr = ipv6h->nexthdr;
	hdroff = ipv6_skip_exthdr(skb, iphdroff + sizeof(*ipv6h),
				  &nexthdr, &frag_off);
	if (hdroff < 0)
		goto manip_addr;

	if ((frag_off & htons(~0x7)) == 0 &&
	    !l4proto->manip_pkt(skb, &nf_nat_l3proto_ipv6, iphdroff, hdroff,
				target, maniptype))
		return false;
manip_addr:
	if (maniptype == NF_NAT_MANIP_SRC)
		ipv6h->saddr = target->src.u3.in6;
	else
		ipv6h->daddr = target->dst.u3.in6;

	return true;
}

static void nf_nat_ipv6_csum_update(struct sk_buff *skb,
				    unsigned int iphdroff, __sum16 *check,
				    const struct nf_conntrack_tuple *t,
				    enum nf_nat_manip_type maniptype)
{
	const struct ipv6hdr *ipv6h = (struct ipv6hdr *)(skb->data + iphdroff);
	const struct in6_addr *oldip, *newip;

	if (maniptype == NF_NAT_MANIP_SRC) {
		oldip = &ipv6h->saddr;
		newip = &t->src.u3.in6;
	} else {
		oldip = &ipv6h->daddr;
		newip = &t->dst.u3.in6;
	}
	inet_proto_csum_replace16(check, skb, oldip->s6_addr32,
				  newip->s6_addr32, true);
}

static void nf_nat_ipv6_csum_recalc(struct sk_buff *skb,
				    u8 proto, void *data, __sum16 *check,
				    int datalen, int oldlen)
{
	if (skb->ip_summed != CHECKSUM_PARTIAL) {
		const struct ipv6hdr *ipv6h = ipv6_hdr(skb);

		skb->ip_summed = CHECKSUM_PARTIAL;
		skb->csum_start = skb_headroom(skb) + skb_network_offset(skb) +
			(data - (void *)skb->data);
		skb->csum_offset = (void *)check - data;
		*check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
					  datalen, proto, 0);
	} else
		inet_proto_csum_replace2(check, skb,
					 htons(oldlen), htons(datalen), true);
}

#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
static int nf_nat_ipv6_nlattr_to_range(struct nlattr *tb[],
				       struct nf_nat_range *range)
{
	if (tb[CTA_NAT_V6_MINIP]) {
		nla_memcpy(&range->min_addr.ip6, tb[CTA_NAT_V6_MINIP],
			   sizeof(struct in6_addr));
		range->flags |= NF_NAT_RANGE_MAP_IPS;
	}

	if (tb[CTA_NAT_V6_MAXIP])
		nla_memcpy(&range->max_addr.ip6, tb[CTA_NAT_V6_MAXIP],
			   sizeof(struct in6_addr));
	else
		range->max_addr = range->min_addr;

	return 0;
}
#endif

static const struct nf_nat_l3proto nf_nat_l3proto_ipv6 = {
	.l3proto		= NFPROTO_IPV6,
	.secure_port		= nf_nat_ipv6_secure_port,
	.in_range		= nf_nat_ipv6_in_range,
	.manip_pkt		= nf_nat_ipv6_manip_pkt,
	.csum_update		= nf_nat_ipv6_csum_update,
	.csum_recalc		= nf_nat_ipv6_csum_recalc,
#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
	.nlattr_to_range	= nf_nat_ipv6_nlattr_to_range,
#endif
#ifdef CONFIG_XFRM
	.decode_session	= nf_nat_ipv6_decode_session,
#endif
};

int nf_nat_icmpv6_reply_translation(struct sk_buff *skb,
				    struct nf_conn *ct,
				    enum ip_conntrack_info ctinfo,
				    unsigned int hooknum,
				    unsigned int hdrlen)
{
	struct {
		struct icmp6hdr	icmp6;
		struct ipv6hdr	ip6;
	} *inside;
	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
	enum nf_nat_manip_type manip = HOOK2MANIP(hooknum);
	const struct nf_nat_l4proto *l4proto;
	struct nf_conntrack_tuple target;
	unsigned long statusbit;

	NF_CT_ASSERT(ctinfo == IP_CT_RELATED || ctinfo == IP_CT_RELATED_REPLY);

	if (!skb_make_writable(skb, hdrlen + sizeof(*inside)))
		return 0;
	if (nf_ip6_checksum(skb, hooknum, hdrlen, IPPROTO_ICMPV6))
		return 0;

	inside = (void *)skb->data + hdrlen;
	if (inside->icmp6.icmp6_type == NDISC_REDIRECT) {
		if ((ct->status & IPS_NAT_DONE_MASK) != IPS_NAT_DONE_MASK)
			return 0;
		if (ct->status & IPS_NAT_MASK)
			return 0;
	}

	if (manip == NF_NAT_MANIP_SRC)
		statusbit = IPS_SRC_NAT;
	else
		statusbit = IPS_DST_NAT;

	/* Invert if this is reply direction */
	if (dir == IP_CT_DIR_REPLY)
		statusbit ^= IPS_NAT_MASK;

	if (!(ct->status & statusbit))
		return 1;

	l4proto = __nf_nat_l4proto_find(NFPROTO_IPV6, inside->ip6.nexthdr);
	if (!nf_nat_ipv6_manip_pkt(skb, hdrlen + sizeof(inside->icmp6),
				   l4proto, &ct->tuplehash[!dir].tuple, !manip))
		return 0;

	if (skb->ip_summed != CHECKSUM_PARTIAL) {
		struct ipv6hdr *ipv6h = ipv6_hdr(skb);
		inside = (void *)skb->data + hdrlen;
		inside->icmp6.icmp6_cksum = 0;
		inside->icmp6.icmp6_cksum =
			csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
					skb->len - hdrlen, IPPROTO_ICMPV6,
					csum_partial(&inside->icmp6,
						     skb->len - hdrlen, 0));
	}

	nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
	l4proto = __nf_nat_l4proto_find(NFPROTO_IPV6, IPPROTO_ICMPV6);
	if (!nf_nat_ipv6_manip_pkt(skb, 0, l4proto, &target, manip))
		return 0;

	return 1;
}
EXPORT_SYMBOL_GPL(nf_nat_icmpv6_reply_translation);

unsigned int
nf_nat_ipv6_fn(void *priv, struct sk_buff *skb,
	       const struct nf_hook_state *state,
	       unsigned int (*do_chain)(void *priv,
					struct sk_buff *skb,
					const struct nf_hook_state *state,
					struct nf_conn *ct))
{
	struct nf_conn *ct;
	enum ip_conntrack_info ctinfo;
	struct nf_conn_nat *nat;
	enum nf_nat_manip_type maniptype = HOOK2MANIP(state->hook);
	__be16 frag_off;
	int hdrlen;
	u8 nexthdr;

	ct = nf_ct_get(skb, &ctinfo);
	/* Can't track?  It's not due to stress, or conntrack would
	 * have dropped it.  Hence it's the user's responsibilty to
	 * packet filter it out, or implement conntrack/NAT for that
	 * protocol. 8) --RR
	 */
	if (!ct)
		return NF_ACCEPT;

	/* Don't try to NAT if this packet is not conntracked */
	if (nf_ct_is_untracked(ct))
		return NF_ACCEPT;

	nat = nf_ct_nat_ext_add(ct);
	if (nat == NULL)
		return NF_ACCEPT;

	switch (ctinfo) {
	case IP_CT_RELATED:
	case IP_CT_RELATED_REPLY:
		nexthdr = ipv6_hdr(skb)->nexthdr;
		hdrlen = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr),
					  &nexthdr, &frag_off);

		if (hdrlen >= 0 && nexthdr == IPPROTO_ICMPV6) {
			if (!nf_nat_icmpv6_reply_translation(skb, ct, ctinfo,
							     state->hook,
							     hdrlen))
				return NF_DROP;
			else
				return NF_ACCEPT;
		}
		/* Fall thru... (Only ICMPs can be IP_CT_IS_REPLY) */
	case IP_CT_NEW:
		/* Seen it before?  This can happen for loopback, retrans,
		 * or local packets.
		 */
		if (!nf_nat_initialized(ct, maniptype)) {
			unsigned int ret;

			ret = do_chain(priv, skb, state, ct);
			if (ret != NF_ACCEPT)
				return ret;

			if (nf_nat_initialized(ct, HOOK2MANIP(state->hook)))
				break;

			ret = nf_nat_alloc_null_binding(ct, state->hook);
			if (ret != NF_ACCEPT)
				return ret;
		} else {
			pr_debug("Already setup manip %s for ct %p\n",
				 maniptype == NF_NAT_MANIP_SRC ? "SRC" : "DST",
				 ct);
			if (nf_nat_oif_changed(state->hook, ctinfo, nat, state->out))
				goto oif_changed;
		}
		break;

	default:
		/* ESTABLISHED */
		NF_CT_ASSERT(ctinfo == IP_CT_ESTABLISHED ||
			     ctinfo == IP_CT_ESTABLISHED_REPLY);
		if (nf_nat_oif_changed(state->hook, ctinfo, nat, state->out))
			goto oif_changed;
	}

	return nf_nat_packet(ct, ctinfo, state->hook, skb);

oif_changed:
	nf_ct_kill_acct(ct, ctinfo, skb);
	return NF_DROP;
}
EXPORT_SYMBOL_GPL(nf_nat_ipv6_fn);

unsigned int
nf_nat_ipv6_in(void *priv, struct sk_buff *skb,
	       const struct nf_hook_state *state,
	       unsigned int (*do_chain)(void *priv,
					struct sk_buff *skb,
					const struct nf_hook_state *state,
					struct nf_conn *ct))
{
	unsigned int ret;
	struct in6_addr daddr = ipv6_hdr(skb)->daddr;

	ret = nf_nat_ipv6_fn(priv, skb, state, do_chain);
	if (ret != NF_DROP && ret != NF_STOLEN &&
	    ipv6_addr_cmp(&daddr, &ipv6_hdr(skb)->daddr))
		skb_dst_drop(skb);

	return ret;
}
EXPORT_SYMBOL_GPL(nf_nat_ipv6_in);

unsigned int
nf_nat_ipv6_out(void *priv, struct sk_buff *skb,
		const struct nf_hook_state *state,
		unsigned int (*do_chain)(void *priv,
					 struct sk_buff *skb,
					 const struct nf_hook_state *state,
					 struct nf_conn *ct))
{
#ifdef CONFIG_XFRM
	const struct nf_conn *ct;
	enum ip_conntrack_info ctinfo;
	int err;
#endif
	unsigned int ret;

	/* root is playing with raw sockets. */
	if (skb->len < sizeof(struct ipv6hdr))
		return NF_ACCEPT;

	ret = nf_nat_ipv6_fn(priv, skb, state, do_chain);
#ifdef CONFIG_XFRM
	if (ret != NF_DROP && ret != NF_STOLEN &&
	    !(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
	    (ct = nf_ct_get(skb, &ctinfo)) != NULL) {
		enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);

		if (!nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3,
				      &ct->tuplehash[!dir].tuple.dst.u3) ||
		    (ct->tuplehash[dir].tuple.dst.protonum != IPPROTO_ICMPV6 &&
		     ct->tuplehash[dir].tuple.src.u.all !=
		     ct->tuplehash[!dir].tuple.dst.u.all)) {
			err = nf_xfrm_me_harder(state->net, skb, AF_INET6);
			if (err < 0)
				ret = NF_DROP_ERR(err);
		}
	}
#endif
	return ret;
}
EXPORT_SYMBOL_GPL(nf_nat_ipv6_out);

unsigned int
nf_nat_ipv6_local_fn(void *priv, struct sk_buff *skb,
		     const struct nf_hook_state *state,
		     unsigned int (*do_chain)(void *priv,
					      struct sk_buff *skb,
					      const struct nf_hook_state *state,
					      struct nf_conn *ct))
{
	const struct nf_conn *ct;
	enum ip_conntrack_info ctinfo;
	unsigned int ret;
	int err;

	/* root is playing with raw sockets. */
	if (skb->len < sizeof(struct ipv6hdr))
		return NF_ACCEPT;

	ret = nf_nat_ipv6_fn(priv, skb, state, do_chain);
	if (ret != NF_DROP && ret != NF_STOLEN &&
	    (ct = nf_ct_get(skb, &ctinfo)) != NULL) {
		enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);

		if (!nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.dst.u3,
				      &ct->tuplehash[!dir].tuple.src.u3)) {
			err = ip6_route_me_harder(state->net, skb);
			if (err < 0)
				ret = NF_DROP_ERR(err);
		}
#ifdef CONFIG_XFRM
		else if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
			 ct->tuplehash[dir].tuple.dst.protonum != IPPROTO_ICMPV6 &&
			 ct->tuplehash[dir].tuple.dst.u.all !=
			 ct->tuplehash[!dir].tuple.src.u.all) {
			err = nf_xfrm_me_harder(state->net, skb, AF_INET6);
			if (err < 0)
				ret = NF_DROP_ERR(err);
		}
#endif
	}
	return ret;
}
EXPORT_SYMBOL_GPL(nf_nat_ipv6_local_fn);

static int __init nf_nat_l3proto_ipv6_init(void)
{
	int err;

	err = nf_nat_l4proto_register(NFPROTO_IPV6, &nf_nat_l4proto_icmpv6);
	if (err < 0)
		goto err1;
	err = nf_nat_l3proto_register(&nf_nat_l3proto_ipv6);
	if (err < 0)
		goto err2;
	return err;

err2:
	nf_nat_l4proto_unregister(NFPROTO_IPV6, &nf_nat_l4proto_icmpv6);
err1:
	return err;
}

static void __exit nf_nat_l3proto_ipv6_exit(void)
{
	nf_nat_l3proto_unregister(&nf_nat_l3proto_ipv6);
	nf_nat_l4proto_unregister(NFPROTO_IPV6, &nf_nat_l4proto_icmpv6);
}

MODULE_LICENSE("GPL");
MODULE_ALIAS("nf-nat-" __stringify(AF_INET6));

module_init(nf_nat_l3proto_ipv6_init);
module_exit(nf_nat_l3proto_ipv6_exit);
Commit	Line	Data
58a317f1 PM	1	/*
	2	* Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	* published by the Free Software Foundation.
	7	*
	8	* Development of IPv6 NAT funded by Astaro.
	9	*/
	10	#include <linux/types.h>
	11	#include <linux/module.h>
	12	#include <linux/skbuff.h>
	13	#include <linux/ipv6.h>
	14	#include <linux/netfilter.h>
	15	#include <linux/netfilter_ipv6.h>
	16	#include <net/secure_seq.h>
	17	#include <net/checksum.h>
2c969322	18	#include <net/ip6_checksum.h>
58a317f1 PM	19	#include <net/ip6_route.h>
	20	#include <net/ipv6.h>
	21
	22	#include <net/netfilter/nf_conntrack_core.h>
	23	#include <net/netfilter/nf_conntrack.h>
	24	#include <net/netfilter/nf_nat_core.h>
	25	#include <net/netfilter/nf_nat_l3proto.h>
	26	#include <net/netfilter/nf_nat_l4proto.h>
	27
	28	static const struct nf_nat_l3proto nf_nat_l3proto_ipv6;
	29
	30	#ifdef CONFIG_XFRM
	31	static void nf_nat_ipv6_decode_session(struct sk_buff *skb,
	32	const struct nf_conn *ct,
	33	enum ip_conntrack_dir dir,
	34	unsigned long statusbit,
	35	struct flowi *fl)
	36	{
	37	const struct nf_conntrack_tuple *t = &ct->tuplehash[dir].tuple;
	38	struct flowi6 *fl6 = &fl->u.ip6;
	39
	40	if (ct->status & statusbit) {
	41	fl6->daddr = t->dst.u3.in6;
	42	if (t->dst.protonum == IPPROTO_TCP \|\|
	43	t->dst.protonum == IPPROTO_UDP \|\|
	44	t->dst.protonum == IPPROTO_UDPLITE \|\|
	45	t->dst.protonum == IPPROTO_DCCP \|\|
	46	t->dst.protonum == IPPROTO_SCTP)
	47	fl6->fl6_dport = t->dst.u.all;
	48	}
	49
	50	statusbit ^= IPS_NAT_MASK;
	51
	52	if (ct->status & statusbit) {
	53	fl6->saddr = t->src.u3.in6;
	54	if (t->dst.protonum == IPPROTO_TCP \|\|
	55	t->dst.protonum == IPPROTO_UDP \|\|
	56	t->dst.protonum == IPPROTO_UDPLITE \|\|
	57	t->dst.protonum == IPPROTO_DCCP \|\|
	58	t->dst.protonum == IPPROTO_SCTP)
	59	fl6->fl6_sport = t->src.u.all;
	60	}
	61	}
	62	#endif
	63
	64	static bool nf_nat_ipv6_in_range(const struct nf_conntrack_tuple *t,
	65	const struct nf_nat_range *range)
	66	{
	67	return ipv6_addr_cmp(&t->src.u3.in6, &range->min_addr.in6) >= 0 &&
	68	ipv6_addr_cmp(&t->src.u3.in6, &range->max_addr.in6) <= 0;
	69	}
	70
	71	static u32 nf_nat_ipv6_secure_port(const struct nf_conntrack_tuple *t,
	72	__be16 dport)
	73	{
	74	return secure_ipv6_port_ephemeral(t->src.u3.ip6, t->dst.u3.ip6, dport);
	75	}
	76
	77	static bool nf_nat_ipv6_manip_pkt(struct sk_buff *skb,
	78	unsigned int iphdroff,
	79	const struct nf_nat_l4proto *l4proto,
	80	const struct nf_conntrack_tuple *target,
	81	enum nf_nat_manip_type maniptype)
	82	{
83	struct ipv6hdr *ipv6h;
84	__be16 frag_off;
85	int hdroff;
86	u8 nexthdr;
87
88	if (!skb_make_writable(skb, iphdroff + sizeof(*ipv6h)))
89	return false;
90
91	ipv6h = (void *)skb->data + iphdroff;
92	nexthdr = ipv6h->nexthdr;
93	hdroff = ipv6_skip_exthdr(skb, iphdroff + sizeof(*ipv6h),
94	&nexthdr, &frag_off);
95	if (hdroff < 0)
96	goto manip_addr;
97
98	if ((frag_off & htons(~0x7)) == 0 &&
99	!l4proto->manip_pkt(skb, &nf_nat_l3proto_ipv6, iphdroff, hdroff,
100	target, maniptype))
101	return false;
102	manip_addr:
103	if (maniptype == NF_NAT_MANIP_SRC)
104	ipv6h->saddr = target->src.u3.in6;
105	else
106	ipv6h->daddr = target->dst.u3.in6;
107
108	return true;
109	}
110
111	static void nf_nat_ipv6_csum_update(struct sk_buff *skb,
112	unsigned int iphdroff, __sum16 *check,
113	const struct nf_conntrack_tuple *t,
114	enum nf_nat_manip_type maniptype)
115	{
116	const struct ipv6hdr ipv6h = (struct ipv6hdr )(skb->data + iphdroff);
117	const struct in6_addr oldip, newip;
118
119	if (maniptype == NF_NAT_MANIP_SRC) {
120	oldip = &ipv6h->saddr;
121	newip = &t->src.u3.in6;
122	} else {
123	oldip = &ipv6h->daddr;
124	newip = &t->dst.u3.in6;
125	}
126	inet_proto_csum_replace16(check, skb, oldip->s6_addr32,
4b048d6d	127	newip->s6_addr32, true);
58a317f1 PM	128	}
	129
	130	static void nf_nat_ipv6_csum_recalc(struct sk_buff *skb,
	131	u8 proto, void data, __sum16 check,
	132	int datalen, int oldlen)
	133	{
58a317f1	134	if (skb->ip_summed != CHECKSUM_PARTIAL) {
26461905 JR	135	const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
	136
	137	skb->ip_summed = CHECKSUM_PARTIAL;
	138	skb->csum_start = skb_headroom(skb) + skb_network_offset(skb) +
	139	(data - (void *)skb->data);
	140	skb->csum_offset = (void *)check - data;
	141	*check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
	142	datalen, proto, 0);
58a317f1 PM	143	} else
58a317f1 PM	144	inet_proto_csum_replace2(check, skb,
4b048d6d	145	htons(oldlen), htons(datalen), true);
58a317f1 PM	146	}
58a317f1 PM	147
24de3d37	148	#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
58a317f1 PM	149	static int nf_nat_ipv6_nlattr_to_range(struct nlattr *tb[],
	150	struct nf_nat_range *range)
	151	{
	152	if (tb[CTA_NAT_V6_MINIP]) {
	153	nla_memcpy(&range->min_addr.ip6, tb[CTA_NAT_V6_MINIP],
	154	sizeof(struct in6_addr));
	155	range->flags \|= NF_NAT_RANGE_MAP_IPS;
	156	}
	157
	158	if (tb[CTA_NAT_V6_MAXIP])
	159	nla_memcpy(&range->max_addr.ip6, tb[CTA_NAT_V6_MAXIP],
	160	sizeof(struct in6_addr));
	161	else
	162	range->max_addr = range->min_addr;
	163
	164	return 0;
	165	}
24de3d37	166	#endif
58a317f1 PM	167
	168	static const struct nf_nat_l3proto nf_nat_l3proto_ipv6 = {
	169	.l3proto = NFPROTO_IPV6,
	170	.secure_port = nf_nat_ipv6_secure_port,
	171	.in_range = nf_nat_ipv6_in_range,
	172	.manip_pkt = nf_nat_ipv6_manip_pkt,
	173	.csum_update = nf_nat_ipv6_csum_update,
	174	.csum_recalc = nf_nat_ipv6_csum_recalc,
24de3d37	175	#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
58a317f1	176	.nlattr_to_range = nf_nat_ipv6_nlattr_to_range,
24de3d37	177	#endif
58a317f1 PM	178	#ifdef CONFIG_XFRM
	179	.decode_session = nf_nat_ipv6_decode_session,
	180	#endif
	181	};
	182
	183	int nf_nat_icmpv6_reply_translation(struct sk_buff *skb,
	184	struct nf_conn *ct,
	185	enum ip_conntrack_info ctinfo,
	186	unsigned int hooknum,
	187	unsigned int hdrlen)
	188	{
	189	struct {
	190	struct icmp6hdr icmp6;
	191	struct ipv6hdr ip6;
	192	} *inside;
	193	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
	194	enum nf_nat_manip_type manip = HOOK2MANIP(hooknum);
	195	const struct nf_nat_l4proto *l4proto;
	196	struct nf_conntrack_tuple target;
	197	unsigned long statusbit;
	198
	199	NF_CT_ASSERT(ctinfo == IP_CT_RELATED \|\| ctinfo == IP_CT_RELATED_REPLY);
	200
	201	if (!skb_make_writable(skb, hdrlen + sizeof(*inside)))
	202	return 0;
	203	if (nf_ip6_checksum(skb, hooknum, hdrlen, IPPROTO_ICMPV6))
	204	return 0;
	205
	206	inside = (void *)skb->data + hdrlen;
	207	if (inside->icmp6.icmp6_type == NDISC_REDIRECT) {
	208	if ((ct->status & IPS_NAT_DONE_MASK) != IPS_NAT_DONE_MASK)
	209	return 0;
	210	if (ct->status & IPS_NAT_MASK)
	211	return 0;
	212	}
	213
	214	if (manip == NF_NAT_MANIP_SRC)
	215	statusbit = IPS_SRC_NAT;
	216	else
	217	statusbit = IPS_DST_NAT;
	218
	219	/* Invert if this is reply direction */
	220	if (dir == IP_CT_DIR_REPLY)
	221	statusbit ^= IPS_NAT_MASK;
	222
	223	if (!(ct->status & statusbit))
	224	return 1;
	225
	226	l4proto = __nf_nat_l4proto_find(NFPROTO_IPV6, inside->ip6.nexthdr);
	227	if (!nf_nat_ipv6_manip_pkt(skb, hdrlen + sizeof(inside->icmp6),
	228	l4proto, &ct->tuplehash[!dir].tuple, !manip))
	229	return 0;
	230
	231	if (skb->ip_summed != CHECKSUM_PARTIAL) {
	232	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
	233	inside = (void *)skb->data + hdrlen;
	234	inside->icmp6.icmp6_cksum = 0;
	235	inside->icmp6.icmp6_cksum =
	236	csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
	237	skb->len - hdrlen, IPPROTO_ICMPV6,
	238	csum_partial(&inside->icmp6,
	239	skb->len - hdrlen, 0));
	240	}
	241
242	nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
243	l4proto = __nf_nat_l4proto_find(NFPROTO_IPV6, IPPROTO_ICMPV6);
244	if (!nf_nat_ipv6_manip_pkt(skb, 0, l4proto, &target, manip))
245	return 0;
246
247	return 1;
248	}
249	EXPORT_SYMBOL_GPL(nf_nat_icmpv6_reply_translation);
250
2a5538e9	251	unsigned int
06198b34	252	nf_nat_ipv6_fn(void priv, struct sk_buff skb,
8fe22382	253	const struct nf_hook_state *state,
06198b34	254	unsigned int (do_chain)(void priv,
2a5538e9	255	struct sk_buff *skb,
8fe22382	256	const struct nf_hook_state *state,
2a5538e9 PNA	257	struct nf_conn *ct))
	258	{
	259	struct nf_conn *ct;
	260	enum ip_conntrack_info ctinfo;
	261	struct nf_conn_nat *nat;
082a758f	262	enum nf_nat_manip_type maniptype = HOOK2MANIP(state->hook);
2a5538e9 PNA	263	__be16 frag_off;
	264	int hdrlen;
	265	u8 nexthdr;
	266
	267	ct = nf_ct_get(skb, &ctinfo);
	268	/* Can't track? It's not due to stress, or conntrack would
	269	* have dropped it. Hence it's the user's responsibilty to
	270	* packet filter it out, or implement conntrack/NAT for that
	271	* protocol. 8) --RR
	272	*/
	273	if (!ct)
	274	return NF_ACCEPT;
	275
	276	/* Don't try to NAT if this packet is not conntracked */
	277	if (nf_ct_is_untracked(ct))
	278	return NF_ACCEPT;
	279
	280	nat = nf_ct_nat_ext_add(ct);
	281	if (nat == NULL)
	282	return NF_ACCEPT;
	283
	284	switch (ctinfo) {
	285	case IP_CT_RELATED:
	286	case IP_CT_RELATED_REPLY:
	287	nexthdr = ipv6_hdr(skb)->nexthdr;
	288	hdrlen = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr),
	289	&nexthdr, &frag_off);
	290
	291	if (hdrlen >= 0 && nexthdr == IPPROTO_ICMPV6) {
	292	if (!nf_nat_icmpv6_reply_translation(skb, ct, ctinfo,
082a758f	293	state->hook,
2a5538e9 PNA	294	hdrlen))
	295	return NF_DROP;
	296	else
	297	return NF_ACCEPT;
	298	}
	299	/* Fall thru... (Only ICMPs can be IP_CT_IS_REPLY) */
	300	case IP_CT_NEW:
	301	/* Seen it before? This can happen for loopback, retrans,
	302	* or local packets.
	303	*/
	304	if (!nf_nat_initialized(ct, maniptype)) {
	305	unsigned int ret;
	306
06198b34	307	ret = do_chain(priv, skb, state, ct);
2a5538e9 PNA	308	if (ret != NF_ACCEPT)
	309	return ret;
	310
082a758f	311	if (nf_nat_initialized(ct, HOOK2MANIP(state->hook)))
2a5538e9 PNA	312	break;
2a5538e9 PNA	313
082a758f	314	ret = nf_nat_alloc_null_binding(ct, state->hook);
2a5538e9 PNA	315	if (ret != NF_ACCEPT)
	316	return ret;
	317	} else {
	318	pr_debug("Already setup manip %s for ct %p\n",
	319	maniptype == NF_NAT_MANIP_SRC ? "SRC" : "DST",
	320	ct);
082a758f	321	if (nf_nat_oif_changed(state->hook, ctinfo, nat, state->out))
2a5538e9 PNA	322	goto oif_changed;
	323	}
	324	break;
	325
	326	default:
	327	/* ESTABLISHED */
	328	NF_CT_ASSERT(ctinfo == IP_CT_ESTABLISHED \|\|
	329	ctinfo == IP_CT_ESTABLISHED_REPLY);
082a758f	330	if (nf_nat_oif_changed(state->hook, ctinfo, nat, state->out))
2a5538e9 PNA	331	goto oif_changed;
	332	}
	333
082a758f	334	return nf_nat_packet(ct, ctinfo, state->hook, skb);
2a5538e9 PNA	335
	336	oif_changed:
	337	nf_ct_kill_acct(ct, ctinfo, skb);
	338	return NF_DROP;
	339	}
	340	EXPORT_SYMBOL_GPL(nf_nat_ipv6_fn);
	341
	342	unsigned int
06198b34	343	nf_nat_ipv6_in(void priv, struct sk_buff skb,
8fe22382	344	const struct nf_hook_state *state,
06198b34	345	unsigned int (do_chain)(void priv,
2a5538e9	346	struct sk_buff *skb,
8fe22382	347	const struct nf_hook_state *state,
2a5538e9 PNA	348	struct nf_conn *ct))
	349	{
	350	unsigned int ret;
	351	struct in6_addr daddr = ipv6_hdr(skb)->daddr;
	352
06198b34	353	ret = nf_nat_ipv6_fn(priv, skb, state, do_chain);
2a5538e9 PNA	354	if (ret != NF_DROP && ret != NF_STOLEN &&
	355	ipv6_addr_cmp(&daddr, &ipv6_hdr(skb)->daddr))
	356	skb_dst_drop(skb);
	357
	358	return ret;
	359	}
	360	EXPORT_SYMBOL_GPL(nf_nat_ipv6_in);
	361
	362	unsigned int
06198b34	363	nf_nat_ipv6_out(void priv, struct sk_buff skb,
8fe22382	364	const struct nf_hook_state *state,
06198b34	365	unsigned int (do_chain)(void priv,
2a5538e9	366	struct sk_buff *skb,
8fe22382	367	const struct nf_hook_state *state,
2a5538e9 PNA	368	struct nf_conn *ct))
	369	{
	370	#ifdef CONFIG_XFRM
	371	const struct nf_conn *ct;
	372	enum ip_conntrack_info ctinfo;
	373	int err;
	374	#endif
	375	unsigned int ret;
	376
	377	/* root is playing with raw sockets. */
	378	if (skb->len < sizeof(struct ipv6hdr))
	379	return NF_ACCEPT;
	380
06198b34	381	ret = nf_nat_ipv6_fn(priv, skb, state, do_chain);
2a5538e9 PNA	382	#ifdef CONFIG_XFRM
	383	if (ret != NF_DROP && ret != NF_STOLEN &&
	384	!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
	385	(ct = nf_ct_get(skb, &ctinfo)) != NULL) {
	386	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
	387
	388	if (!nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3,
	389	&ct->tuplehash[!dir].tuple.dst.u3) \|\|
	390	(ct->tuplehash[dir].tuple.dst.protonum != IPPROTO_ICMPV6 &&
	391	ct->tuplehash[dir].tuple.src.u.all !=
	392	ct->tuplehash[!dir].tuple.dst.u.all)) {
c7af6483	393	err = nf_xfrm_me_harder(state->net, skb, AF_INET6);
2a5538e9 PNA	394	if (err < 0)
	395	ret = NF_DROP_ERR(err);
	396	}
	397	}
	398	#endif
	399	return ret;
	400	}
	401	EXPORT_SYMBOL_GPL(nf_nat_ipv6_out);
	402
	403	unsigned int
06198b34	404	nf_nat_ipv6_local_fn(void priv, struct sk_buff skb,
8fe22382	405	const struct nf_hook_state *state,
06198b34	406	unsigned int (do_chain)(void priv,
2a5538e9	407	struct sk_buff *skb,
8fe22382	408	const struct nf_hook_state *state,
2a5538e9 PNA	409	struct nf_conn *ct))
	410	{
	411	const struct nf_conn *ct;
	412	enum ip_conntrack_info ctinfo;
	413	unsigned int ret;
	414	int err;
	415
	416	/* root is playing with raw sockets. */
	417	if (skb->len < sizeof(struct ipv6hdr))
	418	return NF_ACCEPT;
	419
06198b34	420	ret = nf_nat_ipv6_fn(priv, skb, state, do_chain);
2a5538e9 PNA	421	if (ret != NF_DROP && ret != NF_STOLEN &&
	422	(ct = nf_ct_get(skb, &ctinfo)) != NULL) {
	423	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
	424
	425	if (!nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.dst.u3,
	426	&ct->tuplehash[!dir].tuple.src.u3)) {
5f5d74d7	427	err = ip6_route_me_harder(state->net, skb);
2a5538e9 PNA	428	if (err < 0)
	429	ret = NF_DROP_ERR(err);
	430	}
	431	#ifdef CONFIG_XFRM
	432	else if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
	433	ct->tuplehash[dir].tuple.dst.protonum != IPPROTO_ICMPV6 &&
	434	ct->tuplehash[dir].tuple.dst.u.all !=
	435	ct->tuplehash[!dir].tuple.src.u.all) {
c7af6483	436	err = nf_xfrm_me_harder(state->net, skb, AF_INET6);
2a5538e9 PNA	437	if (err < 0)
	438	ret = NF_DROP_ERR(err);
	439	}
	440	#endif
	441	}
	442	return ret;
	443	}
	444	EXPORT_SYMBOL_GPL(nf_nat_ipv6_local_fn);
	445
58a317f1 PM	446	static int __init nf_nat_l3proto_ipv6_init(void)
	447	{
	448	int err;
	449
	450	err = nf_nat_l4proto_register(NFPROTO_IPV6, &nf_nat_l4proto_icmpv6);
	451	if (err < 0)
	452	goto err1;
	453	err = nf_nat_l3proto_register(&nf_nat_l3proto_ipv6);
	454	if (err < 0)
	455	goto err2;
	456	return err;
	457
	458	err2:
	459	nf_nat_l4proto_unregister(NFPROTO_IPV6, &nf_nat_l4proto_icmpv6);
	460	err1:
	461	return err;
	462	}
	463
	464	static void __exit nf_nat_l3proto_ipv6_exit(void)
	465	{
	466	nf_nat_l3proto_unregister(&nf_nat_l3proto_ipv6);
	467	nf_nat_l4proto_unregister(NFPROTO_IPV6, &nf_nat_l4proto_icmpv6);
	468	}
	469
	470	MODULE_LICENSE("GPL");
	471	MODULE_ALIAS("nf-nat-" __stringify(AF_INET6));
	472
	473	module_init(nf_nat_l3proto_ipv6_init);
	474	module_exit(nf_nat_l3proto_ipv6_exit);