1 files changed, 856 insertions, 0 deletions

diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c
new file mode 100644
index 0000000..5f2f910
--- /dev/null
+++ b/net/netfilter/nf_nat_core.c
@@ -0,0 +1,856 @@
+/*
+ * (C) 1999-2001 Paul `Rusty' Russell
+ * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
+ * (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.
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/timer.h>
+#include <linux/skbuff.h>
+#include <linux/gfp.h>
+#include <net/xfrm.h>
+#include <linux/jhash.h>
+#include <linux/rtnetlink.h>
+
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_core.h>
+#include <net/netfilter/nf_nat.h>
+#include <net/netfilter/nf_nat_l3proto.h>
+#include <net/netfilter/nf_nat_l4proto.h>
+#include <net/netfilter/nf_nat_core.h>
+#include <net/netfilter/nf_nat_helper.h>
+#include <net/netfilter/nf_conntrack_helper.h>
+#include <net/netfilter/nf_conntrack_l3proto.h>
+#include <net/netfilter/nf_conntrack_zones.h>
+#include <linux/netfilter/nf_nat.h>
+
+static DEFINE_SPINLOCK(nf_nat_lock);
+
+static DEFINE_MUTEX(nf_nat_proto_mutex);
+static const struct nf_nat_l3proto __rcu *nf_nat_l3protos[NFPROTO_NUMPROTO]
+						__read_mostly;
+static const struct nf_nat_l4proto __rcu **nf_nat_l4protos[NFPROTO_NUMPROTO]
+						__read_mostly;
+
+
+inline const struct nf_nat_l3proto *
+__nf_nat_l3proto_find(u8 family)
+{
+	return rcu_dereference(nf_nat_l3protos[family]);
+}
+
+inline const struct nf_nat_l4proto *
+__nf_nat_l4proto_find(u8 family, u8 protonum)
+{
+	return rcu_dereference(nf_nat_l4protos[family][protonum]);
+}
+EXPORT_SYMBOL_GPL(__nf_nat_l4proto_find);
+
+#ifdef CONFIG_XFRM
+static void __nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl)
+{
+	const struct nf_nat_l3proto *l3proto;
+	const struct nf_conn *ct;
+	enum ip_conntrack_info ctinfo;
+	enum ip_conntrack_dir dir;
+	unsigned  long statusbit;
+	u8 family;
+
+	ct = nf_ct_get(skb, &ctinfo);
+	if (ct == NULL)
+		return;
+
+	family = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num;
+	rcu_read_lock();
+	l3proto = __nf_nat_l3proto_find(family);
+	if (l3proto == NULL)
+		goto out;
+
+	dir = CTINFO2DIR(ctinfo);
+	if (dir == IP_CT_DIR_ORIGINAL)
+		statusbit = IPS_DST_NAT;
+	else
+		statusbit = IPS_SRC_NAT;
+
+	l3proto->decode_session(skb, ct, dir, statusbit, fl);
+out:
+	rcu_read_unlock();
+}
+
+int nf_xfrm_me_harder(struct sk_buff *skb, unsigned int family)
+{
+	struct flowi fl;
+	unsigned int hh_len;
+	struct dst_entry *dst;
+
+	if (xfrm_decode_session(skb, &fl, family) < 0)
+		return -1;
+
+	dst = skb_dst(skb);
+	if (dst->xfrm)
+		dst = ((struct xfrm_dst *)dst)->route;
+	dst_hold(dst);
+
+	dst = xfrm_lookup(dev_net(dst->dev), dst, &fl, skb->sk, 0);
+	if (IS_ERR(dst))
+		return -1;
+
+	skb_dst_drop(skb);
+	skb_dst_set(skb, dst);
+
+	/* Change in oif may mean change in hh_len. */
+	hh_len = skb_dst(skb)->dev->hard_header_len;
+	if (skb_headroom(skb) < hh_len &&
+	    pskb_expand_head(skb, hh_len - skb_headroom(skb), 0, GFP_ATOMIC))
+		return -1;
+	return 0;
+}
+EXPORT_SYMBOL(nf_xfrm_me_harder);
+#endif /* CONFIG_XFRM */
+
+/* We keep an extra hash for each conntrack, for fast searching. */
+static inline unsigned int
+hash_by_src(const struct net *net, u16 zone,
+	    const struct nf_conntrack_tuple *tuple)
+{
+	unsigned int hash;
+
+	/* Original src, to ensure we map it consistently if poss. */
+	hash = jhash2((u32 *)&tuple->src, sizeof(tuple->src) / sizeof(u32),
+		      tuple->dst.protonum ^ zone ^ nf_conntrack_hash_rnd);
+	return ((u64)hash * net->ct.nat_htable_size) >> 32;
+}
+
+/* Is this tuple already taken? (not by us) */
+int
+nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple,
+		  const struct nf_conn *ignored_conntrack)
+{
+	/* Conntrack tracking doesn't keep track of outgoing tuples; only
+	 * incoming ones.  NAT means they don't have a fixed mapping,
+	 * so we invert the tuple and look for the incoming reply.
+	 *
+	 * We could keep a separate hash if this proves too slow.
+	 */
+	struct nf_conntrack_tuple reply;
+
+	nf_ct_invert_tuplepr(&reply, tuple);
+	return nf_conntrack_tuple_taken(&reply, ignored_conntrack);
+}
+EXPORT_SYMBOL(nf_nat_used_tuple);
+
+/* If we source map this tuple so reply looks like reply_tuple, will
+ * that meet the constraints of range.
+ */
+static int in_range(const struct nf_nat_l3proto *l3proto,
+		    const struct nf_nat_l4proto *l4proto,
+		    const struct nf_conntrack_tuple *tuple,
+		    const struct nf_nat_range *range)
+{
+	/* If we are supposed to map IPs, then we must be in the
+	 * range specified, otherwise let this drag us onto a new src IP.
+	 */
+	if (range->flags & NF_NAT_RANGE_MAP_IPS &&
+	    !l3proto->in_range(tuple, range))
+		return 0;
+
+	if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) ||
+	    l4proto->in_range(tuple, NF_NAT_MANIP_SRC,
+			      &range->min_proto, &range->max_proto))
+		return 1;
+
+	return 0;
+}
+
+static inline int
+same_src(const struct nf_conn *ct,
+	 const struct nf_conntrack_tuple *tuple)
+{
+	const struct nf_conntrack_tuple *t;
+
+	t = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
+	return (t->dst.protonum == tuple->dst.protonum &&
+		nf_inet_addr_cmp(&t->src.u3, &tuple->src.u3) &&
+		t->src.u.all == tuple->src.u.all);
+}
+
+/* Only called for SRC manip */
+static int
+find_appropriate_src(struct net *net, u16 zone,
+		     const struct nf_nat_l3proto *l3proto,
+		     const struct nf_nat_l4proto *l4proto,
+		     const struct nf_conntrack_tuple *tuple,
+		     struct nf_conntrack_tuple *result,
+		     const struct nf_nat_range *range)
+{
+	unsigned int h = hash_by_src(net, zone, tuple);
+	const struct nf_conn_nat *nat;
+	const struct nf_conn *ct;
+	const struct hlist_node *n;
+
+	hlist_for_each_entry_rcu(nat, n, &net->ct.nat_bysource[h], bysource) {
+		ct = nat->ct;
+		if (same_src(ct, tuple) && nf_ct_zone(ct) == zone) {
+			/* Copy source part from reply tuple. */
+			nf_ct_invert_tuplepr(result,
+				       &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
+			result->dst = tuple->dst;
+
+			if (in_range(l3proto, l4proto, result, range))
+				return 1;
+		}
+	}
+	return 0;
+}
+
+/* For [FUTURE] fragmentation handling, we want the least-used
+ * src-ip/dst-ip/proto triple.  Fairness doesn't come into it.  Thus
+ * if the range specifies 1.2.3.4 ports 10000-10005 and 1.2.3.5 ports
+ * 1-65535, we don't do pro-rata allocation based on ports; we choose
+ * the ip with the lowest src-ip/dst-ip/proto usage.
+ */
+static void
+find_best_ips_proto(u16 zone, struct nf_conntrack_tuple *tuple,
+		    const struct nf_nat_range *range,
+		    const struct nf_conn *ct,
+		    enum nf_nat_manip_type maniptype)
+{
+	union nf_inet_addr *var_ipp;
+	unsigned int i, max;
+	/* Host order */
+	u32 minip, maxip, j, dist;
+	bool full_range;
+
+	/* No IP mapping?  Do nothing. */
+	if (!(range->flags & NF_NAT_RANGE_MAP_IPS))
+		return;
+
+	if (maniptype == NF_NAT_MANIP_SRC)
+		var_ipp = &tuple->src.u3;
+	else
+		var_ipp = &tuple->dst.u3;
+
+	/* Fast path: only one choice. */
+	if (nf_inet_addr_cmp(&range->min_addr, &range->max_addr)) {
+		*var_ipp = range->min_addr;
+		return;
+	}
+
+	if (nf_ct_l3num(ct) == NFPROTO_IPV4)
+		max = sizeof(var_ipp->ip) / sizeof(u32) - 1;
+	else
+		max = sizeof(var_ipp->ip6) / sizeof(u32) - 1;
+
+	/* Hashing source and destination IPs gives a fairly even
+	 * spread in practice (if there are a small number of IPs
+	 * involved, there usually aren't that many connections
+	 * anyway).  The consistency means that servers see the same
+	 * client coming from the same IP (some Internet Banking sites
+	 * like this), even across reboots.
+	 */
+	j = jhash2((u32 *)&tuple->src.u3, sizeof(tuple->src.u3) / sizeof(u32),
+		   range->flags & NF_NAT_RANGE_PERSISTENT ?
+			0 : (__force u32)tuple->dst.u3.all[max] ^ zone);
+
+	full_range = false;
+	for (i = 0; i <= max; i++) {
+		/* If first bytes of the address are at the maximum, use the
+		 * distance. Otherwise use the full range.
+		 */
+		if (!full_range) {
+			minip = ntohl((__force __be32)range->min_addr.all[i]);
+			maxip = ntohl((__force __be32)range->max_addr.all[i]);
+			dist  = maxip - minip + 1;
+		} else {
+			minip = 0;
+			dist  = ~0;
+		}
+
+		var_ipp->all[i] = (__force __u32)
+			htonl(minip + (((u64)j * dist) >> 32));
+		if (var_ipp->all[i] != range->max_addr.all[i])
+			full_range = true;
+
+		if (!(range->flags & NF_NAT_RANGE_PERSISTENT))
+			j ^= (__force u32)tuple->dst.u3.all[i];
+	}
+}
+
+/* Manipulate the tuple into the range given. For NF_INET_POST_ROUTING,
+ * we change the source to map into the range. For NF_INET_PRE_ROUTING
+ * and NF_INET_LOCAL_OUT, we change the destination to map into the
+ * range. It might not be possible to get a unique tuple, but we try.
+ * At worst (or if we race), we will end up with a final duplicate in
+ * __ip_conntrack_confirm and drop the packet. */
+static void
+get_unique_tuple(struct nf_conntrack_tuple *tuple,
+		 const struct nf_conntrack_tuple *orig_tuple,
+		 const struct nf_nat_range *range,
+		 struct nf_conn *ct,
+		 enum nf_nat_manip_type maniptype)
+{
+	const struct nf_nat_l3proto *l3proto;
+	const struct nf_nat_l4proto *l4proto;
+	struct net *net = nf_ct_net(ct);
+	u16 zone = nf_ct_zone(ct);
+
+	rcu_read_lock();
+	l3proto = __nf_nat_l3proto_find(orig_tuple->src.l3num);
+	l4proto = __nf_nat_l4proto_find(orig_tuple->src.l3num,
+					orig_tuple->dst.protonum);
+
+	/* 1) If this srcip/proto/src-proto-part is currently mapped,
+	 * and that same mapping gives a unique tuple within the given
+	 * range, use that.
+	 *
+	 * This is only required for source (ie. NAT/masq) mappings.
+	 * So far, we don't do local source mappings, so multiple
+	 * manips not an issue.
+	 */
+	if (maniptype == NF_NAT_MANIP_SRC &&
+	    !(range->flags & NF_NAT_RANGE_PROTO_RANDOM)) {
+		/* try the original tuple first */
+		if (in_range(l3proto, l4proto, orig_tuple, range)) {
+			if (!nf_nat_used_tuple(orig_tuple, ct)) {
+				*tuple = *orig_tuple;
+				goto out;
+			}
+		} else if (find_appropriate_src(net, zone, l3proto, l4proto,
+						orig_tuple, tuple, range)) {
+			pr_debug("get_unique_tuple: Found current src map\n");
+			if (!nf_nat_used_tuple(tuple, ct))
+				goto out;
+		}
+	}
+
+	/* 2) Select the least-used IP/proto combination in the given range */
+	*tuple = *orig_tuple;
+	find_best_ips_proto(zone, tuple, range, ct, maniptype);
+
+	/* 3) The per-protocol part of the manip is made to map into
+	 * the range to make a unique tuple.
+	 */
+
+	/* Only bother mapping if it's not already in range and unique */
+	if (!(range->flags & NF_NAT_RANGE_PROTO_RANDOM)) {
+		if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
+			if (l4proto->in_range(tuple, maniptype,
+					      &range->min_proto,
+					      &range->max_proto) &&
+			    (range->min_proto.all == range->max_proto.all ||
+			     !nf_nat_used_tuple(tuple, ct)))
+				goto out;
+		} else if (!nf_nat_used_tuple(tuple, ct)) {
+			goto out;
+		}
+	}
+
+	/* Last change: get protocol to try to obtain unique tuple. */
+	l4proto->unique_tuple(l3proto, tuple, range, maniptype, ct);
+out:
+	rcu_read_unlock();
+}
+
+unsigned int
+nf_nat_setup_info(struct nf_conn *ct,
+		  const struct nf_nat_range *range,
+		  enum nf_nat_manip_type maniptype)
+{
+	struct net *net = nf_ct_net(ct);
+	struct nf_conntrack_tuple curr_tuple, new_tuple;
+	struct nf_conn_nat *nat;
+
+	/* nat helper or nfctnetlink also setup binding */
+	nat = nfct_nat(ct);
+	if (!nat) {
+		nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC);
+		if (nat == NULL) {
+			pr_debug("failed to add NAT extension\n");
+			return NF_ACCEPT;
+		}
+	}
+
+	NF_CT_ASSERT(maniptype == NF_NAT_MANIP_SRC ||
+		     maniptype == NF_NAT_MANIP_DST);
+	BUG_ON(nf_nat_initialized(ct, maniptype));
+
+	/* What we've got will look like inverse of reply. Normally
+	 * this is what is in the conntrack, except for prior
+	 * manipulations (future optimization: if num_manips == 0,
+	 * orig_tp = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple)
+	 */
+	nf_ct_invert_tuplepr(&curr_tuple,
+			     &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
+
+	get_unique_tuple(&new_tuple, &curr_tuple, range, ct, maniptype);
+
+	if (!nf_ct_tuple_equal(&new_tuple, &curr_tuple)) {
+		struct nf_conntrack_tuple reply;
+
+		/* Alter conntrack table so will recognize replies. */
+		nf_ct_invert_tuplepr(&reply, &new_tuple);
+		nf_conntrack_alter_reply(ct, &reply);
+
+		/* Non-atomic: we own this at the moment. */
+		if (maniptype == NF_NAT_MANIP_SRC)
+			ct->status |= IPS_SRC_NAT;
+		else
+			ct->status |= IPS_DST_NAT;
+	}
+
+	if (maniptype == NF_NAT_MANIP_SRC) {
+		unsigned int srchash;
+
+		srchash = hash_by_src(net, nf_ct_zone(ct),
+				      &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
+		spin_lock_bh(&nf_nat_lock);
+		/* nf_conntrack_alter_reply might re-allocate extension aera */
+		nat = nfct_nat(ct);
+		nat->ct = ct;
+		hlist_add_head_rcu(&nat->bysource,
+				   &net->ct.nat_bysource[srchash]);
+		spin_unlock_bh(&nf_nat_lock);
+	}
+
+	/* It's done. */
+	if (maniptype == NF_NAT_MANIP_DST)
+		ct->status |= IPS_DST_NAT_DONE;
+	else
+		ct->status |= IPS_SRC_NAT_DONE;
+
+	return NF_ACCEPT;
+}
+EXPORT_SYMBOL(nf_nat_setup_info);
+
+/* Do packet manipulations according to nf_nat_setup_info. */
+unsigned int nf_nat_packet(struct nf_conn *ct,
+			   enum ip_conntrack_info ctinfo,
+			   unsigned int hooknum,
+			   struct sk_buff *skb)
+{
+	const struct nf_nat_l3proto *l3proto;
+	const struct nf_nat_l4proto *l4proto;
+	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+	unsigned long statusbit;
+	enum nf_nat_manip_type mtype = HOOK2MANIP(hooknum);
+
+	if (mtype == NF_NAT_MANIP_SRC)
+		statusbit = IPS_SRC_NAT;
+	else
+		statusbit = IPS_DST_NAT;
+
+	/* Invert if this is reply dir. */
+	if (dir == IP_CT_DIR_REPLY)
+		statusbit ^= IPS_NAT_MASK;
+
+	/* Non-atomic: these bits don't change. */
+	if (ct->status & statusbit) {
+		struct nf_conntrack_tuple target;
+
+		/* We are aiming to look like inverse of other direction. */
+		nf_ct_invert_tuplepr(&target, &ct->tuplehash[!dir].tuple);
+
+		l3proto = __nf_nat_l3proto_find(target.src.l3num);
+		l4proto = __nf_nat_l4proto_find(target.src.l3num,
+						target.dst.protonum);
+		if (!l3proto->manip_pkt(skb, 0, l4proto, &target, mtype))
+			return NF_DROP;
+	}
+	return NF_ACCEPT;
+}
+EXPORT_SYMBOL_GPL(nf_nat_packet);
+
+struct nf_nat_proto_clean {
+	u8	l3proto;
+	u8	l4proto;
+	bool	hash;
+};
+
+/* Clear NAT section of all conntracks, in case we're loaded again. */
+static int nf_nat_proto_clean(struct nf_conn *i, void *data)
+{
+	const struct nf_nat_proto_clean *clean = data;
+	struct nf_conn_nat *nat = nfct_nat(i);
+
+	if (!nat)
+		return 0;
+	if (!(i->status & IPS_SRC_NAT_DONE))
+		return 0;
+	if ((clean->l3proto && nf_ct_l3num(i) != clean->l3proto) ||
+	    (clean->l4proto && nf_ct_protonum(i) != clean->l4proto))
+		return 0;
+
+	if (clean->hash) {
+		spin_lock_bh(&nf_nat_lock);
+		hlist_del_rcu(&nat->bysource);
+		spin_unlock_bh(&nf_nat_lock);
+	} else {
+		memset(nat, 0, sizeof(*nat));
+		i->status &= ~(IPS_NAT_MASK | IPS_NAT_DONE_MASK |
+			       IPS_SEQ_ADJUST);
+	}
+	return 0;
+}
+
+static void nf_nat_l4proto_clean(u8 l3proto, u8 l4proto)
+{
+	struct nf_nat_proto_clean clean = {
+		.l3proto = l3proto,
+		.l4proto = l4proto,
+	};
+	struct net *net;
+
+	rtnl_lock();
+	/* Step 1 - remove from bysource hash */
+	clean.hash = true;
+	for_each_net(net)
+		nf_ct_iterate_cleanup(net, nf_nat_proto_clean, &clean);
+	synchronize_rcu();
+
+	/* Step 2 - clean NAT section */
+	clean.hash = false;
+	for_each_net(net)
+		nf_ct_iterate_cleanup(net, nf_nat_proto_clean, &clean);
+	rtnl_unlock();
+}
+
+static void nf_nat_l3proto_clean(u8 l3proto)
+{
+	struct nf_nat_proto_clean clean = {
+		.l3proto = l3proto,
+	};
+	struct net *net;
+
+	rtnl_lock();
+	/* Step 1 - remove from bysource hash */
+	clean.hash = true;
+	for_each_net(net)
+		nf_ct_iterate_cleanup(net, nf_nat_proto_clean, &clean);
+	synchronize_rcu();
+
+	/* Step 2 - clean NAT section */
+	clean.hash = false;
+	for_each_net(net)
+		nf_ct_iterate_cleanup(net, nf_nat_proto_clean, &clean);
+	rtnl_unlock();
+}
+
+/* Protocol registration. */
+int nf_nat_l4proto_register(u8 l3proto, const struct nf_nat_l4proto *l4proto)
+{
+	const struct nf_nat_l4proto **l4protos;
+	unsigned int i;
+	int ret = 0;
+
+	mutex_lock(&nf_nat_proto_mutex);
+	if (nf_nat_l4protos[l3proto] == NULL) {
+		l4protos = kmalloc(IPPROTO_MAX * sizeof(struct nf_nat_l4proto *),
+				   GFP_KERNEL);
+		if (l4protos == NULL) {
+			ret = -ENOMEM;
+			goto out;
+		}
+
+		for (i = 0; i < IPPROTO_MAX; i++)
+			RCU_INIT_POINTER(l4protos[i], &nf_nat_l4proto_unknown);
+
+		/* Before making proto_array visible to lockless readers,
+		 * we must make sure its content is committed to memory.
+		 */
+		smp_wmb();
+
+		nf_nat_l4protos[l3proto] = l4protos;
+	}
+
+	if (rcu_dereference_protected(
+			nf_nat_l4protos[l3proto][l4proto->l4proto],
+			lockdep_is_held(&nf_nat_proto_mutex)
+			) != &nf_nat_l4proto_unknown) {
+		ret = -EBUSY;
+		goto out;
+	}
+	RCU_INIT_POINTER(nf_nat_l4protos[l3proto][l4proto->l4proto], l4proto);
+ out:
+	mutex_unlock(&nf_nat_proto_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(nf_nat_l4proto_register);
+
+/* No one stores the protocol anywhere; simply delete it. */
+void nf_nat_l4proto_unregister(u8 l3proto, const struct nf_nat_l4proto *l4proto)
+{
+	mutex_lock(&nf_nat_proto_mutex);
+	RCU_INIT_POINTER(nf_nat_l4protos[l3proto][l4proto->l4proto],
+			 &nf_nat_l4proto_unknown);
+	mutex_unlock(&nf_nat_proto_mutex);
+	synchronize_rcu();
+
+	nf_nat_l4proto_clean(l3proto, l4proto->l4proto);
+}
+EXPORT_SYMBOL_GPL(nf_nat_l4proto_unregister);
+
+int nf_nat_l3proto_register(const struct nf_nat_l3proto *l3proto)
+{
+	int err;
+
+	err = nf_ct_l3proto_try_module_get(l3proto->l3proto);
+	if (err < 0)
+		return err;
+
+	mutex_lock(&nf_nat_proto_mutex);
+	RCU_INIT_POINTER(nf_nat_l4protos[l3proto->l3proto][IPPROTO_TCP],
+			 &nf_nat_l4proto_tcp);
+	RCU_INIT_POINTER(nf_nat_l4protos[l3proto->l3proto][IPPROTO_UDP],
+			 &nf_nat_l4proto_udp);
+	mutex_unlock(&nf_nat_proto_mutex);
+
+	RCU_INIT_POINTER(nf_nat_l3protos[l3proto->l3proto], l3proto);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nf_nat_l3proto_register);
+
+void nf_nat_l3proto_unregister(const struct nf_nat_l3proto *l3proto)
+{
+	mutex_lock(&nf_nat_proto_mutex);
+	RCU_INIT_POINTER(nf_nat_l3protos[l3proto->l3proto], NULL);
+	mutex_unlock(&nf_nat_proto_mutex);
+	synchronize_rcu();
+
+	nf_nat_l3proto_clean(l3proto->l3proto);
+	nf_ct_l3proto_module_put(l3proto->l3proto);
+}
+EXPORT_SYMBOL_GPL(nf_nat_l3proto_unregister);
+
+/* No one using conntrack by the time this called. */
+static void nf_nat_cleanup_conntrack(struct nf_conn *ct)
+{
+	struct nf_conn_nat *nat = nf_ct_ext_find(ct, NF_CT_EXT_NAT);
+
+	if (nat == NULL || nat->ct == NULL)
+		return;
+
+	NF_CT_ASSERT(nat->ct->status & IPS_SRC_NAT_DONE);
+
+	spin_lock_bh(&nf_nat_lock);
+	hlist_del_rcu(&nat->bysource);
+	spin_unlock_bh(&nf_nat_lock);
+}
+
+static void nf_nat_move_storage(void *new, void *old)
+{
+	struct nf_conn_nat *new_nat = new;
+	struct nf_conn_nat *old_nat = old;
+	struct nf_conn *ct = old_nat->ct;
+
+	if (!ct || !(ct->status & IPS_SRC_NAT_DONE))
+		return;
+
+	spin_lock_bh(&nf_nat_lock);
+	hlist_replace_rcu(&old_nat->bysource, &new_nat->bysource);
+	spin_unlock_bh(&nf_nat_lock);
+}
+
+static struct nf_ct_ext_type nat_extend __read_mostly = {
+	.len		= sizeof(struct nf_conn_nat),
+	.align		= __alignof__(struct nf_conn_nat),
+	.destroy	= nf_nat_cleanup_conntrack,
+	.move		= nf_nat_move_storage,
+	.id		= NF_CT_EXT_NAT,
+	.flags		= NF_CT_EXT_F_PREALLOC,
+};
+
+#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
+
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netfilter/nfnetlink_conntrack.h>
+
+static const struct nla_policy protonat_nla_policy[CTA_PROTONAT_MAX+1] = {
+	[CTA_PROTONAT_PORT_MIN]	= { .type = NLA_U16 },
+	[CTA_PROTONAT_PORT_MAX]	= { .type = NLA_U16 },
+};
+
+static int nfnetlink_parse_nat_proto(struct nlattr *attr,
+				     const struct nf_conn *ct,
+				     struct nf_nat_range *range)
+{
+	struct nlattr *tb[CTA_PROTONAT_MAX+1];
+	const struct nf_nat_l4proto *l4proto;
+	int err;
+
+	err = nla_parse_nested(tb, CTA_PROTONAT_MAX, attr, protonat_nla_policy);
+	if (err < 0)
+		return err;
+
+	l4proto = __nf_nat_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct));
+	if (l4proto->nlattr_to_range)
+		err = l4proto->nlattr_to_range(tb, range);
+
+	return err;
+}
+
+static const struct nla_policy nat_nla_policy[CTA_NAT_MAX+1] = {
+	[CTA_NAT_V4_MINIP]	= { .type = NLA_U32 },
+	[CTA_NAT_V4_MAXIP]	= { .type = NLA_U32 },
+	[CTA_NAT_V6_MINIP]	= { .len = sizeof(struct in6_addr) },
+	[CTA_NAT_V6_MAXIP]	= { .len = sizeof(struct in6_addr) },
+	[CTA_NAT_PROTO]		= { .type = NLA_NESTED },
+};
+
+static int
+nfnetlink_parse_nat(const struct nlattr *nat,
+		    const struct nf_conn *ct, struct nf_nat_range *range)
+{
+	const struct nf_nat_l3proto *l3proto;
+	struct nlattr *tb[CTA_NAT_MAX+1];
+	int err;
+
+	memset(range, 0, sizeof(*range));
+
+	err = nla_parse_nested(tb, CTA_NAT_MAX, nat, nat_nla_policy);
+	if (err < 0)
+		return err;
+
+	rcu_read_lock();
+	l3proto = __nf_nat_l3proto_find(nf_ct_l3num(ct));
+	if (l3proto == NULL) {
+		err = -EAGAIN;
+		goto out;
+	}
+	err = l3proto->nlattr_to_range(tb, range);
+	if (err < 0)
+		goto out;
+
+	if (!tb[CTA_NAT_PROTO])
+		goto out;
+
+	err = nfnetlink_parse_nat_proto(tb[CTA_NAT_PROTO], ct, range);
+out:
+	rcu_read_unlock();
+	return err;
+}
+
+static int
+nfnetlink_parse_nat_setup(struct nf_conn *ct,
+			  enum nf_nat_manip_type manip,
+			  const struct nlattr *attr)
+{
+	struct nf_nat_range range;
+	int err;
+
+	err = nfnetlink_parse_nat(attr, ct, &range);
+	if (err < 0)
+		return err;
+	if (nf_nat_initialized(ct, manip))
+		return -EEXIST;
+
+	return nf_nat_setup_info(ct, &range, manip);
+}
+#else
+static int
+nfnetlink_parse_nat_setup(struct nf_conn *ct,
+			  enum nf_nat_manip_type manip,
+			  const struct nlattr *attr)
+{
+	return -EOPNOTSUPP;
+}
+#endif
+
+static int __net_init nf_nat_net_init(struct net *net)
+{
+	/* Leave them the same for the moment. */
+	net->ct.nat_htable_size = net->ct.htable_size;
+	net->ct.nat_bysource = nf_ct_alloc_hashtable(&net->ct.nat_htable_size, 0);
+	if (!net->ct.nat_bysource)
+		return -ENOMEM;
+	return 0;
+}
+
+static void __net_exit nf_nat_net_exit(struct net *net)
+{
+	struct nf_nat_proto_clean clean = {};
+
+	nf_ct_iterate_cleanup(net, &nf_nat_proto_clean, &clean);
+	synchronize_rcu();
+	nf_ct_free_hashtable(net->ct.nat_bysource, net->ct.nat_htable_size);
+}
+
+static struct pernet_operations nf_nat_net_ops = {
+	.init = nf_nat_net_init,
+	.exit = nf_nat_net_exit,
+};
+
+static struct nf_ct_helper_expectfn follow_master_nat = {
+	.name		= "nat-follow-master",
+	.expectfn	= nf_nat_follow_master,
+};
+
+static struct nfq_ct_nat_hook nfq_ct_nat = {
+	.seq_adjust	= nf_nat_tcp_seq_adjust,
+};
+
+static int __init nf_nat_init(void)
+{
+	int ret;
+
+	ret = nf_ct_extend_register(&nat_extend);
+	if (ret < 0) {
+		printk(KERN_ERR "nf_nat_core: Unable to register extension\n");
+		return ret;
+	}
+
+	ret = register_pernet_subsys(&nf_nat_net_ops);
+	if (ret < 0)
+		goto cleanup_extend;
+
+	nf_ct_helper_expectfn_register(&follow_master_nat);
+
+	/* Initialize fake conntrack so that NAT will skip it */
+	nf_ct_untracked_status_or(IPS_NAT_DONE_MASK);
+
+	BUG_ON(nf_nat_seq_adjust_hook != NULL);
+	RCU_INIT_POINTER(nf_nat_seq_adjust_hook, nf_nat_seq_adjust);
+	BUG_ON(nfnetlink_parse_nat_setup_hook != NULL);
+	RCU_INIT_POINTER(nfnetlink_parse_nat_setup_hook,
+			   nfnetlink_parse_nat_setup);
+	BUG_ON(nf_ct_nat_offset != NULL);
+	RCU_INIT_POINTER(nf_ct_nat_offset, nf_nat_get_offset);
+	RCU_INIT_POINTER(nfq_ct_nat_hook, &nfq_ct_nat);
+#ifdef CONFIG_XFRM
+	BUG_ON(nf_nat_decode_session_hook != NULL);
+	RCU_INIT_POINTER(nf_nat_decode_session_hook, __nf_nat_decode_session);
+#endif
+	return 0;
+
+ cleanup_extend:
+	nf_ct_extend_unregister(&nat_extend);
+	return ret;
+}
+
+static void __exit nf_nat_cleanup(void)
+{
+	unsigned int i;
+
+	unregister_pernet_subsys(&nf_nat_net_ops);
+	nf_ct_extend_unregister(&nat_extend);
+	nf_ct_helper_expectfn_unregister(&follow_master_nat);
+	RCU_INIT_POINTER(nf_nat_seq_adjust_hook, NULL);
+	RCU_INIT_POINTER(nfnetlink_parse_nat_setup_hook, NULL);
+	RCU_INIT_POINTER(nf_ct_nat_offset, NULL);
+	RCU_INIT_POINTER(nfq_ct_nat_hook, NULL);
+#ifdef CONFIG_XFRM
+	RCU_INIT_POINTER(nf_nat_decode_session_hook, NULL);
+#endif
+	for (i = 0; i < NFPROTO_NUMPROTO; i++)
+		kfree(nf_nat_l4protos[i]);
+	synchronize_net();
+}
+
+MODULE_LICENSE("GPL");
+
+module_init(nf_nat_init);
+module_exit(nf_nat_cleanup);