[deliverable/linux.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, 1);
}

static void nf_nat_ipv6_csum_recalc(struct sk_buff *skb,
				    u8 proto, void *data, __sum16 *check,
				    int datalen, int oldlen)
{
	const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
	struct rt6_info *rt = (struct rt6_info *)skb_dst(skb);

	if (skb->ip_summed != CHECKSUM_PARTIAL) {
		if (!(rt->rt6i_flags & RTF_LOCAL) &&
		    (!skb->dev || skb->dev->features & NETIF_F_V6_CSUM)) {
			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 {
			*check = 0;
			*check = csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
						 datalen, proto,
						 csum_partial(data, datalen,
							      0));
			if (proto == IPPROTO_UDP && !*check)
				*check = CSUM_MANGLED_0;
		}
	} else
		inet_proto_csum_replace2(check, skb,
					 htons(oldlen), htons(datalen), 1);
}

#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(const struct nf_hook_ops *ops, struct sk_buff *skb,
	       const struct net_device *in, const struct net_device *out,
	       unsigned int (*do_chain)(const struct nf_hook_ops *ops,
					struct sk_buff *skb,
					const struct net_device *in,
					const struct net_device *out,
					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(ops->hooknum);
	__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,
							     ops->hooknum,
							     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(ops, skb, in, out, ct);
			if (ret != NF_ACCEPT)
				return ret;

			if (nf_nat_initialized(ct, HOOK2MANIP(ops->hooknum)))
				break;

			ret = nf_nat_alloc_null_binding(ct, ops->hooknum);
			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(ops->hooknum, ctinfo, nat, out))
				goto oif_changed;
		}
		break;

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

	return nf_nat_packet(ct, ctinfo, ops->hooknum, 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(const struct nf_hook_ops *ops, struct sk_buff *skb,
	       const struct net_device *in, const struct net_device *out,
	       unsigned int (*do_chain)(const struct nf_hook_ops *ops,
					struct sk_buff *skb,
					const struct net_device *in,
					const struct net_device *out,
					struct nf_conn *ct))
{
	unsigned int ret;
	struct in6_addr daddr = ipv6_hdr(skb)->daddr;

	ret = nf_nat_ipv6_fn(ops, skb, in, out, 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(const struct nf_hook_ops *ops, struct sk_buff *skb,
		const struct net_device *in, const struct net_device *out,
		unsigned int (*do_chain)(const struct nf_hook_ops *ops,
					 struct sk_buff *skb,
					 const struct net_device *in,
					 const struct net_device *out,
					 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(ops, skb, in, out, 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(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(const struct nf_hook_ops *ops, struct sk_buff *skb,
		     const struct net_device *in, const struct net_device *out,
		     unsigned int (*do_chain)(const struct nf_hook_ops *ops,
					      struct sk_buff *skb,
					      const struct net_device *in,
					      const struct net_device *out,
					      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(ops, skb, in, out, 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(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(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,
127	newip->s6_addr32, 1);
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	{
134	const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
135	struct rt6_info rt = (struct rt6_info )skb_dst(skb);
136
137	if (skb->ip_summed != CHECKSUM_PARTIAL) {
138	if (!(rt->rt6i_flags & RTF_LOCAL) &&
139	(!skb->dev \|\| skb->dev->features & NETIF_F_V6_CSUM)) {
140	skb->ip_summed = CHECKSUM_PARTIAL;
141	skb->csum_start = skb_headroom(skb) +
142	skb_network_offset(skb) +
143	(data - (void *)skb->data);
144	skb->csum_offset = (void *)check - data;
145	*check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
146	datalen, proto, 0);
147	} else {
148	*check = 0;
149	*check = csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
150	datalen, proto,
151	csum_partial(data, datalen,
152	0));
153	if (proto == IPPROTO_UDP && !*check)
154	*check = CSUM_MANGLED_0;
155	}
156	} else
157	inet_proto_csum_replace2(check, skb,
158	htons(oldlen), htons(datalen), 1);
159	}
160
24de3d37	161	#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
58a317f1 PM	162	static int nf_nat_ipv6_nlattr_to_range(struct nlattr *tb[],
	163	struct nf_nat_range *range)
	164	{
	165	if (tb[CTA_NAT_V6_MINIP]) {
	166	nla_memcpy(&range->min_addr.ip6, tb[CTA_NAT_V6_MINIP],
	167	sizeof(struct in6_addr));
	168	range->flags \|= NF_NAT_RANGE_MAP_IPS;
	169	}
	170
	171	if (tb[CTA_NAT_V6_MAXIP])
	172	nla_memcpy(&range->max_addr.ip6, tb[CTA_NAT_V6_MAXIP],
	173	sizeof(struct in6_addr));
	174	else
	175	range->max_addr = range->min_addr;
	176
	177	return 0;
	178	}
24de3d37	179	#endif
58a317f1 PM	180
	181	static const struct nf_nat_l3proto nf_nat_l3proto_ipv6 = {
	182	.l3proto = NFPROTO_IPV6,
	183	.secure_port = nf_nat_ipv6_secure_port,
	184	.in_range = nf_nat_ipv6_in_range,
	185	.manip_pkt = nf_nat_ipv6_manip_pkt,
	186	.csum_update = nf_nat_ipv6_csum_update,
	187	.csum_recalc = nf_nat_ipv6_csum_recalc,
24de3d37	188	#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
58a317f1	189	.nlattr_to_range = nf_nat_ipv6_nlattr_to_range,
24de3d37	190	#endif
58a317f1 PM	191	#ifdef CONFIG_XFRM
	192	.decode_session = nf_nat_ipv6_decode_session,
	193	#endif
	194	};
	195
	196	int nf_nat_icmpv6_reply_translation(struct sk_buff *skb,
	197	struct nf_conn *ct,
	198	enum ip_conntrack_info ctinfo,
	199	unsigned int hooknum,
	200	unsigned int hdrlen)
	201	{
	202	struct {
	203	struct icmp6hdr icmp6;
	204	struct ipv6hdr ip6;
	205	} *inside;
	206	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
	207	enum nf_nat_manip_type manip = HOOK2MANIP(hooknum);
	208	const struct nf_nat_l4proto *l4proto;
	209	struct nf_conntrack_tuple target;
	210	unsigned long statusbit;
	211
	212	NF_CT_ASSERT(ctinfo == IP_CT_RELATED \|\| ctinfo == IP_CT_RELATED_REPLY);
	213
	214	if (!skb_make_writable(skb, hdrlen + sizeof(*inside)))
	215	return 0;
	216	if (nf_ip6_checksum(skb, hooknum, hdrlen, IPPROTO_ICMPV6))
	217	return 0;
	218
	219	inside = (void *)skb->data + hdrlen;
	220	if (inside->icmp6.icmp6_type == NDISC_REDIRECT) {
	221	if ((ct->status & IPS_NAT_DONE_MASK) != IPS_NAT_DONE_MASK)
	222	return 0;
	223	if (ct->status & IPS_NAT_MASK)
	224	return 0;
	225	}
	226
	227	if (manip == NF_NAT_MANIP_SRC)
	228	statusbit = IPS_SRC_NAT;
	229	else
	230	statusbit = IPS_DST_NAT;
	231
	232	/* Invert if this is reply direction */
	233	if (dir == IP_CT_DIR_REPLY)
	234	statusbit ^= IPS_NAT_MASK;
	235
	236	if (!(ct->status & statusbit))
	237	return 1;
	238
	239	l4proto = __nf_nat_l4proto_find(NFPROTO_IPV6, inside->ip6.nexthdr);
	240	if (!nf_nat_ipv6_manip_pkt(skb, hdrlen + sizeof(inside->icmp6),
	241	l4proto, &ct->tuplehash[!dir].tuple, !manip))
	242	return 0;
	243
	244	if (skb->ip_summed != CHECKSUM_PARTIAL) {
	245	struct ipv6hdr *ipv6h = ipv6_hdr(skb);
	246	inside = (void *)skb->data + hdrlen;
	247	inside->icmp6.icmp6_cksum = 0;
	248	inside->icmp6.icmp6_cksum =
	249	csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
	250	skb->len - hdrlen, IPPROTO_ICMPV6,
	251	csum_partial(&inside->icmp6,
	252	skb->len - hdrlen, 0));
	253	}
	254
255	nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
256	l4proto = __nf_nat_l4proto_find(NFPROTO_IPV6, IPPROTO_ICMPV6);
257	if (!nf_nat_ipv6_manip_pkt(skb, 0, l4proto, &target, manip))
258	return 0;
259
260	return 1;
261	}
262	EXPORT_SYMBOL_GPL(nf_nat_icmpv6_reply_translation);
263
2a5538e9 PNA	264	unsigned int
	265	nf_nat_ipv6_fn(const struct nf_hook_ops ops, struct sk_buff skb,
	266	const struct net_device in, const struct net_device out,
	267	unsigned int (do_chain)(const struct nf_hook_ops ops,
	268	struct sk_buff *skb,
	269	const struct net_device *in,
	270	const struct net_device *out,
	271	struct nf_conn *ct))
	272	{
	273	struct nf_conn *ct;
	274	enum ip_conntrack_info ctinfo;
	275	struct nf_conn_nat *nat;
	276	enum nf_nat_manip_type maniptype = HOOK2MANIP(ops->hooknum);
	277	__be16 frag_off;
	278	int hdrlen;
	279	u8 nexthdr;
	280
	281	ct = nf_ct_get(skb, &ctinfo);
	282	/* Can't track? It's not due to stress, or conntrack would
	283	* have dropped it. Hence it's the user's responsibilty to
	284	* packet filter it out, or implement conntrack/NAT for that
	285	* protocol. 8) --RR
	286	*/
	287	if (!ct)
	288	return NF_ACCEPT;
	289
	290	/* Don't try to NAT if this packet is not conntracked */
	291	if (nf_ct_is_untracked(ct))
	292	return NF_ACCEPT;
	293
	294	nat = nf_ct_nat_ext_add(ct);
	295	if (nat == NULL)
	296	return NF_ACCEPT;
	297
	298	switch (ctinfo) {
	299	case IP_CT_RELATED:
	300	case IP_CT_RELATED_REPLY:
	301	nexthdr = ipv6_hdr(skb)->nexthdr;
	302	hdrlen = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr),
	303	&nexthdr, &frag_off);
	304
	305	if (hdrlen >= 0 && nexthdr == IPPROTO_ICMPV6) {
	306	if (!nf_nat_icmpv6_reply_translation(skb, ct, ctinfo,
	307	ops->hooknum,
	308	hdrlen))
	309	return NF_DROP;
	310	else
	311	return NF_ACCEPT;
	312	}
	313	/* Fall thru... (Only ICMPs can be IP_CT_IS_REPLY) */
	314	case IP_CT_NEW:
	315	/* Seen it before? This can happen for loopback, retrans,
	316	* or local packets.
	317	*/
	318	if (!nf_nat_initialized(ct, maniptype)) {
	319	unsigned int ret;
	320
	321	ret = do_chain(ops, skb, in, out, ct);
	322	if (ret != NF_ACCEPT)
	323	return ret;
	324
	325	if (nf_nat_initialized(ct, HOOK2MANIP(ops->hooknum)))
	326	break;
	327
328	ret = nf_nat_alloc_null_binding(ct, ops->hooknum);
329	if (ret != NF_ACCEPT)
330	return ret;
331	} else {
332	pr_debug("Already setup manip %s for ct %p\n",
333	maniptype == NF_NAT_MANIP_SRC ? "SRC" : "DST",
334	ct);
335	if (nf_nat_oif_changed(ops->hooknum, ctinfo, nat, out))
336	goto oif_changed;
337	}
338	break;
339
340	default:
341	/* ESTABLISHED */
342	NF_CT_ASSERT(ctinfo == IP_CT_ESTABLISHED \|\|
343	ctinfo == IP_CT_ESTABLISHED_REPLY);
344	if (nf_nat_oif_changed(ops->hooknum, ctinfo, nat, out))
345	goto oif_changed;
346	}
347
348	return nf_nat_packet(ct, ctinfo, ops->hooknum, skb);
349
350	oif_changed:
351	nf_ct_kill_acct(ct, ctinfo, skb);
352	return NF_DROP;
353	}
354	EXPORT_SYMBOL_GPL(nf_nat_ipv6_fn);
355
356	unsigned int
357	nf_nat_ipv6_in(const struct nf_hook_ops ops, struct sk_buff skb,
358	const struct net_device in, const struct net_device out,
359	unsigned int (do_chain)(const struct nf_hook_ops ops,
360	struct sk_buff *skb,
361	const struct net_device *in,
362	const struct net_device *out,
363	struct nf_conn *ct))
364	{
365	unsigned int ret;
366	struct in6_addr daddr = ipv6_hdr(skb)->daddr;
367
368	ret = nf_nat_ipv6_fn(ops, skb, in, out, do_chain);
369	if (ret != NF_DROP && ret != NF_STOLEN &&
370	ipv6_addr_cmp(&daddr, &ipv6_hdr(skb)->daddr))
371	skb_dst_drop(skb);
372
373	return ret;
374	}
375	EXPORT_SYMBOL_GPL(nf_nat_ipv6_in);
376
377	unsigned int
378	nf_nat_ipv6_out(const struct nf_hook_ops ops, struct sk_buff skb,
379	const struct net_device in, const struct net_device out,
380	unsigned int (do_chain)(const struct nf_hook_ops ops,
381	struct sk_buff *skb,
382	const struct net_device *in,
383	const struct net_device *out,
384	struct nf_conn *ct))
385	{
386	#ifdef CONFIG_XFRM
387	const struct nf_conn *ct;
388	enum ip_conntrack_info ctinfo;
389	int err;
390	#endif
391	unsigned int ret;
392
393	/* root is playing with raw sockets. */
394	if (skb->len < sizeof(struct ipv6hdr))
395	return NF_ACCEPT;
396
397	ret = nf_nat_ipv6_fn(ops, skb, in, out, do_chain);
398	#ifdef CONFIG_XFRM
399	if (ret != NF_DROP && ret != NF_STOLEN &&
400	!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
401	(ct = nf_ct_get(skb, &ctinfo)) != NULL) {
402	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
403
404	if (!nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3,
405	&ct->tuplehash[!dir].tuple.dst.u3) \|\|
406	(ct->tuplehash[dir].tuple.dst.protonum != IPPROTO_ICMPV6 &&
407	ct->tuplehash[dir].tuple.src.u.all !=
408	ct->tuplehash[!dir].tuple.dst.u.all)) {
409	err = nf_xfrm_me_harder(skb, AF_INET6);
410	if (err < 0)
411	ret = NF_DROP_ERR(err);
412	}
413	}
414	#endif
415	return ret;
416	}
417	EXPORT_SYMBOL_GPL(nf_nat_ipv6_out);
418
419	unsigned int
420	nf_nat_ipv6_local_fn(const struct nf_hook_ops ops, struct sk_buff skb,
421	const struct net_device in, const struct net_device out,
422	unsigned int (do_chain)(const struct nf_hook_ops ops,
423	struct sk_buff *skb,
424	const struct net_device *in,
425	const struct net_device *out,
426	struct nf_conn *ct))
427	{
428	const struct nf_conn *ct;
429	enum ip_conntrack_info ctinfo;
430	unsigned int ret;
431	int err;
432
433	/* root is playing with raw sockets. */
434	if (skb->len < sizeof(struct ipv6hdr))
435	return NF_ACCEPT;
436
437	ret = nf_nat_ipv6_fn(ops, skb, in, out, do_chain);
438	if (ret != NF_DROP && ret != NF_STOLEN &&
439	(ct = nf_ct_get(skb, &ctinfo)) != NULL) {
440	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
441
442	if (!nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.dst.u3,
443	&ct->tuplehash[!dir].tuple.src.u3)) {
444	err = ip6_route_me_harder(skb);
445	if (err < 0)
446	ret = NF_DROP_ERR(err);
447	}
448	#ifdef CONFIG_XFRM
449	else if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
450	ct->tuplehash[dir].tuple.dst.protonum != IPPROTO_ICMPV6 &&
451	ct->tuplehash[dir].tuple.dst.u.all !=
452	ct->tuplehash[!dir].tuple.src.u.all) {
453	err = nf_xfrm_me_harder(skb, AF_INET6);
454	if (err < 0)
455	ret = NF_DROP_ERR(err);
456	}
457	#endif
458	}
459	return ret;
460	}
461	EXPORT_SYMBOL_GPL(nf_nat_ipv6_local_fn);
462
58a317f1 PM	463	static int __init nf_nat_l3proto_ipv6_init(void)
	464	{
	465	int err;
	466
	467	err = nf_nat_l4proto_register(NFPROTO_IPV6, &nf_nat_l4proto_icmpv6);
	468	if (err < 0)
	469	goto err1;
	470	err = nf_nat_l3proto_register(&nf_nat_l3proto_ipv6);
	471	if (err < 0)
	472	goto err2;
	473	return err;
	474
	475	err2:
	476	nf_nat_l4proto_unregister(NFPROTO_IPV6, &nf_nat_l4proto_icmpv6);
	477	err1:
	478	return err;
	479	}
	480
	481	static void __exit nf_nat_l3proto_ipv6_exit(void)
	482	{
	483	nf_nat_l3proto_unregister(&nf_nat_l3proto_ipv6);
	484	nf_nat_l4proto_unregister(NFPROTO_IPV6, &nf_nat_l4proto_icmpv6);
	485	}
	486
	487	MODULE_LICENSE("GPL");
	488	MODULE_ALIAS("nf-nat-" __stringify(AF_INET6));
	489
	490	module_init(nf_nat_l3proto_ipv6_init);
	491	module_exit(nf_nat_l3proto_ipv6_exit);