netfilter: add protocol independent NAT core

Convert the IPv4 NAT implementation to a protocol independent core and
address family specific modules.

Signed-off-by: Patrick McHardy <kaber@trash.net>

17 files changed, 2190 insertions, 13 deletions

diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index c19b214ffd57..91adddae20a4 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -356,6 +356,30 @@ config NETFILTER_NETLINK_QUEUE_CT
 	  If this option is enabled, NFQUEUE can include Connection Tracking
 	  information together with the packet is the enqueued via NFNETLINK.
 
+config NF_NAT
+	tristate
+
+config NF_NAT_NEEDED
+	bool
+	depends on NF_NAT
+	default y
+
+config NF_NAT_PROTO_DCCP
+	tristate
+	depends on NF_NAT && NF_CT_PROTO_DCCP
+	default NF_NAT && NF_CT_PROTO_DCCP
+
+config NF_NAT_PROTO_UDPLITE
+	tristate
+	depends on NF_NAT && NF_CT_PROTO_UDPLITE
+	default NF_NAT && NF_CT_PROTO_UDPLITE
+
+config NF_NAT_PROTO_SCTP
+	tristate
+	default NF_NAT && NF_CT_PROTO_SCTP
+	depends on NF_NAT && NF_CT_PROTO_SCTP
+	select LIBCRC32C
+
 endif # NF_CONNTRACK
 
 # transparent proxy support
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 1c5160f2278e..09c9451bc510 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -43,6 +43,17 @@ obj-$(CONFIG_NF_CONNTRACK_SANE) += nf_conntrack_sane.o
 obj-$(CONFIG_NF_CONNTRACK_SIP) += nf_conntrack_sip.o
 obj-$(CONFIG_NF_CONNTRACK_TFTP) += nf_conntrack_tftp.o
 
+nf_nat-y	:= nf_nat_core.o nf_nat_proto_unknown.o nf_nat_proto_common.o \
+		   nf_nat_proto_udp.o nf_nat_proto_tcp.o nf_nat_helper.o
+
+obj-$(CONFIG_NF_NAT) += nf_nat.o
+obj-$(CONFIG_NF_NAT) += xt_nat.o
+
+# NAT protocols (nf_nat)
+obj-$(CONFIG_NF_NAT_PROTO_DCCP) += nf_nat_proto_dccp.o
+obj-$(CONFIG_NF_NAT_PROTO_UDPLITE) += nf_nat_proto_udplite.o
+obj-$(CONFIG_NF_NAT_PROTO_SCTP) += nf_nat_proto_sctp.o
+
 # transparent proxy support
 obj-$(CONFIG_NETFILTER_TPROXY) += nf_tproxy_core.o
 
diff --git a/net/netfilter/core.c b/net/netfilter/core.c
index 8f4b0b2b6f80..e61b3ac9591b 100644
--- a/net/netfilter/core.c
+++ b/net/netfilter/core.c
@@ -275,6 +275,11 @@ EXPORT_SYMBOL_GPL(nfq_ct_nat_hook);
 
 #endif /* CONFIG_NF_CONNTRACK */
 
+#ifdef CONFIG_NF_NAT_NEEDED
+void (*nf_nat_decode_session_hook)(struct sk_buff *, struct flowi *);
+EXPORT_SYMBOL(nf_nat_decode_session_hook);
+#endif
+
 #ifdef CONFIG_PROC_FS
 struct proc_dir_entry *proc_net_netfilter;
 EXPORT_SYMBOL(proc_net_netfilter);
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index cf4875565d67..f83e79defed9 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -55,6 +55,12 @@ int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct,
 				      const struct nlattr *attr) __read_mostly;
 EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook);
 
+int (*nf_nat_seq_adjust_hook)(struct sk_buff *skb,
+			      struct nf_conn *ct,
+			      enum ip_conntrack_info ctinfo,
+			      unsigned int protoff);
+EXPORT_SYMBOL_GPL(nf_nat_seq_adjust_hook);
+
 DEFINE_SPINLOCK(nf_conntrack_lock);
 EXPORT_SYMBOL_GPL(nf_conntrack_lock);
 
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index da4fc37a8578..966f5133a384 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -45,7 +45,7 @@
 #include <net/netfilter/nf_conntrack_timestamp.h>
 #ifdef CONFIG_NF_NAT_NEEDED
 #include <net/netfilter/nf_nat_core.h>
-#include <net/netfilter/nf_nat_protocol.h>
+#include <net/netfilter/nf_nat_l4proto.h>
 #include <net/netfilter/nf_nat_helper.h>
 #endif
 
@@ -1096,13 +1096,14 @@ ctnetlink_parse_nat_setup(struct nf_conn *ct,
 			  const struct nlattr *attr)
 {
 	typeof(nfnetlink_parse_nat_setup_hook) parse_nat_setup;
+	int err;
 
 	parse_nat_setup = rcu_dereference(nfnetlink_parse_nat_setup_hook);
 	if (!parse_nat_setup) {
 #ifdef CONFIG_MODULES
 		rcu_read_unlock();
 		nfnl_unlock();
-		if (request_module("nf-nat-ipv4") < 0) {
+		if (request_module("nf-nat") < 0) {
 			nfnl_lock();
 			rcu_read_lock();
 			return -EOPNOTSUPP;
@@ -1115,7 +1116,26 @@ ctnetlink_parse_nat_setup(struct nf_conn *ct,
 		return -EOPNOTSUPP;
 	}
 
-	return parse_nat_setup(ct, manip, attr);
+	err = parse_nat_setup(ct, manip, attr);
+	if (err == -EAGAIN) {
+#ifdef CONFIG_MODULES
+		rcu_read_unlock();
+		spin_unlock_bh(&nf_conntrack_lock);
+		nfnl_unlock();
+		if (request_module("nf-nat-%u", nf_ct_l3num(ct)) < 0) {
+			nfnl_lock();
+			spin_lock_bh(&nf_conntrack_lock);
+			rcu_read_lock();
+			return -EOPNOTSUPP;
+		}
+		nfnl_lock();
+		spin_lock_bh(&nf_conntrack_lock);
+		rcu_read_lock();
+#else
+		err = -EOPNOTSUPP;
+#endif
+	}
+	return err;
 }
 #endif
 
@@ -1979,6 +1999,8 @@ nla_put_failure:
 	return -1;
 }
 
+static const union nf_inet_addr any_addr;
+
 static int
 ctnetlink_exp_dump_expect(struct sk_buff *skb,
 			  const struct nf_conntrack_expect *exp)
@@ -2005,7 +2027,8 @@ ctnetlink_exp_dump_expect(struct sk_buff *skb,
 		goto nla_put_failure;
 
 #ifdef CONFIG_NF_NAT_NEEDED
-	if (exp->saved_ip || exp->saved_proto.all) {
+	if (!nf_inet_addr_cmp(&exp->saved_addr, &any_addr) ||
+	    exp->saved_proto.all) {
 		nest_parms = nla_nest_start(skb, CTA_EXPECT_NAT | NLA_F_NESTED);
 		if (!nest_parms)
 			goto nla_put_failure;
@@ -2014,7 +2037,7 @@ ctnetlink_exp_dump_expect(struct sk_buff *skb,
 			goto nla_put_failure;
 
 		nat_tuple.src.l3num = nf_ct_l3num(master);
-		nat_tuple.src.u3.ip = exp->saved_ip;
+		nat_tuple.src.u3 = exp->saved_addr;
 		nat_tuple.dst.protonum = nf_ct_protonum(master);
 		nat_tuple.src.u = exp->saved_proto;
 
@@ -2410,7 +2433,7 @@ ctnetlink_parse_expect_nat(const struct nlattr *attr,
 	if (err < 0)
 		return err;
 
-	exp->saved_ip = nat_tuple.src.u3.ip;
+	exp->saved_addr = nat_tuple.src.u3;
 	exp->saved_proto = nat_tuple.src.u;
 	exp->dir = ntohl(nla_get_be32(tb[CTA_EXPECT_NAT_DIR]));
 
diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c
index a5ac11ebef33..9c2cc716f4a5 100644
--- a/net/netfilter/nf_conntrack_proto_tcp.c
+++ b/net/netfilter/nf_conntrack_proto_tcp.c
@@ -505,10 +505,10 @@ static inline s16 nat_offset(const struct nf_conn *ct,
 
 	return get_offset != NULL ? get_offset(ct, dir, seq) : 0;
 }
-#define NAT_OFFSET(pf, ct, dir, seq) \
-	(pf == NFPROTO_IPV4 ? nat_offset(ct, dir, seq) : 0)
+#define NAT_OFFSET(ct, dir, seq) \
+	(nat_offset(ct, dir, seq))
 #else
-#define NAT_OFFSET(pf, ct, dir, seq)	0
+#define NAT_OFFSET(ct, dir, seq)	0
 #endif
 
 static bool tcp_in_window(const struct nf_conn *ct,
@@ -541,7 +541,7 @@ static bool tcp_in_window(const struct nf_conn *ct,
 		tcp_sack(skb, dataoff, tcph, &sack);
 
 	/* Take into account NAT sequence number mangling */
-	receiver_offset = NAT_OFFSET(pf, ct, !dir, ack - 1);
+	receiver_offset = NAT_OFFSET(ct, !dir, ack - 1);
 	ack -= receiver_offset;
 	sack -= receiver_offset;
 
diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c
index 590f0abaab8c..d5174902db37 100644
--- a/net/netfilter/nf_conntrack_sip.c
+++ b/net/netfilter/nf_conntrack_sip.c
@@ -946,11 +946,11 @@ static int set_expected_rtp_rtcp(struct sk_buff *skb, unsigned int protoff,
 			break;
 #ifdef CONFIG_NF_NAT_NEEDED
 		if (exp->tuple.src.l3num == AF_INET && !direct_rtp &&
-		    (exp->saved_ip != exp->tuple.dst.u3.ip ||
+		    (exp->saved_addr.ip != exp->tuple.dst.u3.ip ||
 		     exp->saved_proto.udp.port != exp->tuple.dst.u.udp.port) &&
 		    ct->status & IPS_NAT_MASK) {
-			daddr->ip		= exp->saved_ip;
-			tuple.dst.u3.ip		= exp->saved_ip;
+			daddr->ip		= exp->saved_addr.ip;
+			tuple.dst.u3.ip		= exp->saved_addr.ip;
 			tuple.dst.u.udp.port	= exp->saved_proto.udp.port;
 			direct_rtp = 1;
 		} else
diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c
new file mode 100644
index 000000000000..c577b753fb9a
--- /dev/null
+++ b/net/netfilter/nf_nat_core.c
@@ -0,0 +1,854 @@
+/*
+ * (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)) {
+				rcu_read_unlock();
+				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),
+		   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 ((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_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);
diff --git a/net/netfilter/nf_nat_helper.c b/net/netfilter/nf_nat_helper.c
new file mode 100644
index 000000000000..23c2b38676a6
--- /dev/null
+++ b/net/netfilter/nf_nat_helper.c
@@ -0,0 +1,435 @@
+/* nf_nat_helper.c - generic support functions for NAT helpers
+ *
+ * (C) 2000-2002 Harald Welte <laforge@netfilter.org>
+ * (C) 2003-2006 Netfilter Core Team <coreteam@netfilter.org>
+ *
+ * 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/gfp.h>
+#include <linux/types.h>
+#include <linux/skbuff.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
+#include <net/tcp.h>
+
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_helper.h>
+#include <net/netfilter/nf_conntrack_ecache.h>
+#include <net/netfilter/nf_conntrack_expect.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>
+
+#define DUMP_OFFSET(x) \
+	pr_debug("offset_before=%d, offset_after=%d, correction_pos=%u\n", \
+		 x->offset_before, x->offset_after, x->correction_pos);
+
+static DEFINE_SPINLOCK(nf_nat_seqofs_lock);
+
+/* Setup TCP sequence correction given this change at this sequence */
+static inline void
+adjust_tcp_sequence(u32 seq,
+		    int sizediff,
+		    struct nf_conn *ct,
+		    enum ip_conntrack_info ctinfo)
+{
+	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+	struct nf_conn_nat *nat = nfct_nat(ct);
+	struct nf_nat_seq *this_way = &nat->seq[dir];
+
+	pr_debug("adjust_tcp_sequence: seq = %u, sizediff = %d\n",
+		 seq, sizediff);
+
+	pr_debug("adjust_tcp_sequence: Seq_offset before: ");
+	DUMP_OFFSET(this_way);
+
+	spin_lock_bh(&nf_nat_seqofs_lock);
+
+	/* SYN adjust. If it's uninitialized, or this is after last
+	 * correction, record it: we don't handle more than one
+	 * adjustment in the window, but do deal with common case of a
+	 * retransmit */
+	if (this_way->offset_before == this_way->offset_after ||
+	    before(this_way->correction_pos, seq)) {
+		this_way->correction_pos = seq;
+		this_way->offset_before = this_way->offset_after;
+		this_way->offset_after += sizediff;
+	}
+	spin_unlock_bh(&nf_nat_seqofs_lock);
+
+	pr_debug("adjust_tcp_sequence: Seq_offset after: ");
+	DUMP_OFFSET(this_way);
+}
+
+/* Get the offset value, for conntrack */
+s16 nf_nat_get_offset(const struct nf_conn *ct,
+		      enum ip_conntrack_dir dir,
+		      u32 seq)
+{
+	struct nf_conn_nat *nat = nfct_nat(ct);
+	struct nf_nat_seq *this_way;
+	s16 offset;
+
+	if (!nat)
+		return 0;
+
+	this_way = &nat->seq[dir];
+	spin_lock_bh(&nf_nat_seqofs_lock);
+	offset = after(seq, this_way->correction_pos)
+		 ? this_way->offset_after : this_way->offset_before;
+	spin_unlock_bh(&nf_nat_seqofs_lock);
+
+	return offset;
+}
+
+/* Frobs data inside this packet, which is linear. */
+static void mangle_contents(struct sk_buff *skb,
+			    unsigned int dataoff,
+			    unsigned int match_offset,
+			    unsigned int match_len,
+			    const char *rep_buffer,
+			    unsigned int rep_len)
+{
+	unsigned char *data;
+
+	BUG_ON(skb_is_nonlinear(skb));
+	data = skb_network_header(skb) + dataoff;
+
+	/* move post-replacement */
+	memmove(data + match_offset + rep_len,
+		data + match_offset + match_len,
+		skb->tail - (skb->network_header + dataoff +
+			     match_offset + match_len));
+
+	/* insert data from buffer */
+	memcpy(data + match_offset, rep_buffer, rep_len);
+
+	/* update skb info */
+	if (rep_len > match_len) {
+		pr_debug("nf_nat_mangle_packet: Extending packet by "
+			 "%u from %u bytes\n", rep_len - match_len, skb->len);
+		skb_put(skb, rep_len - match_len);
+	} else {
+		pr_debug("nf_nat_mangle_packet: Shrinking packet from "
+			 "%u from %u bytes\n", match_len - rep_len, skb->len);
+		__skb_trim(skb, skb->len + rep_len - match_len);
+	}
+
+	if (nf_ct_l3num((struct nf_conn *)skb->nfct) == NFPROTO_IPV4) {
+		/* fix IP hdr checksum information */
+		ip_hdr(skb)->tot_len = htons(skb->len);
+		ip_send_check(ip_hdr(skb));
+	} else
+		ipv6_hdr(skb)->payload_len =
+			htons(skb->len - sizeof(struct ipv6hdr));
+}
+
+/* Unusual, but possible case. */
+static int enlarge_skb(struct sk_buff *skb, unsigned int extra)
+{
+	if (skb->len + extra > 65535)
+		return 0;
+
+	if (pskb_expand_head(skb, 0, extra - skb_tailroom(skb), GFP_ATOMIC))
+		return 0;
+
+	return 1;
+}
+
+void nf_nat_set_seq_adjust(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
+			   __be32 seq, s16 off)
+{
+	if (!off)
+		return;
+	set_bit(IPS_SEQ_ADJUST_BIT, &ct->status);
+	adjust_tcp_sequence(ntohl(seq), off, ct, ctinfo);
+	nf_conntrack_event_cache(IPCT_NATSEQADJ, ct);
+}
+EXPORT_SYMBOL_GPL(nf_nat_set_seq_adjust);
+
+void nf_nat_tcp_seq_adjust(struct sk_buff *skb, struct nf_conn *ct,
+			   u32 ctinfo, int off)
+{
+	const struct tcphdr *th;
+
+	if (nf_ct_protonum(ct) != IPPROTO_TCP)
+		return;
+
+	th = (struct tcphdr *)(skb_network_header(skb)+ ip_hdrlen(skb));
+	nf_nat_set_seq_adjust(ct, ctinfo, th->seq, off);
+}
+EXPORT_SYMBOL_GPL(nf_nat_tcp_seq_adjust);
+
+/* Generic function for mangling variable-length address changes inside
+ * NATed TCP connections (like the PORT XXX,XXX,XXX,XXX,XXX,XXX
+ * command in FTP).
+ *
+ * Takes care about all the nasty sequence number changes, checksumming,
+ * skb enlargement, ...
+ *
+ * */
+int __nf_nat_mangle_tcp_packet(struct sk_buff *skb,
+			       struct nf_conn *ct,
+			       enum ip_conntrack_info ctinfo,
+			       unsigned int protoff,
+			       unsigned int match_offset,
+			       unsigned int match_len,
+			       const char *rep_buffer,
+			       unsigned int rep_len, bool adjust)
+{
+	const struct nf_nat_l3proto *l3proto;
+	struct tcphdr *tcph;
+	int oldlen, datalen;
+
+	if (!skb_make_writable(skb, skb->len))
+		return 0;
+
+	if (rep_len > match_len &&
+	    rep_len - match_len > skb_tailroom(skb) &&
+	    !enlarge_skb(skb, rep_len - match_len))
+		return 0;
+
+	SKB_LINEAR_ASSERT(skb);
+
+	tcph = (void *)skb->data + protoff;
+
+	oldlen = skb->len - protoff;
+	mangle_contents(skb, protoff + tcph->doff*4,
+			match_offset, match_len, rep_buffer, rep_len);
+
+	datalen = skb->len - protoff;
+
+	l3proto = __nf_nat_l3proto_find(nf_ct_l3num(ct));
+	l3proto->csum_recalc(skb, IPPROTO_TCP, tcph, &tcph->check,
+			     datalen, oldlen);
+
+	if (adjust && rep_len != match_len)
+		nf_nat_set_seq_adjust(ct, ctinfo, tcph->seq,
+				      (int)rep_len - (int)match_len);
+
+	return 1;
+}
+EXPORT_SYMBOL(__nf_nat_mangle_tcp_packet);
+
+/* Generic function for mangling variable-length address changes inside
+ * NATed UDP connections (like the CONNECT DATA XXXXX MESG XXXXX INDEX XXXXX
+ * command in the Amanda protocol)
+ *
+ * Takes care about all the nasty sequence number changes, checksumming,
+ * skb enlargement, ...
+ *
+ * XXX - This function could be merged with nf_nat_mangle_tcp_packet which
+ *       should be fairly easy to do.
+ */
+int
+nf_nat_mangle_udp_packet(struct sk_buff *skb,
+			 struct nf_conn *ct,
+			 enum ip_conntrack_info ctinfo,
+			 unsigned int protoff,
+			 unsigned int match_offset,
+			 unsigned int match_len,
+			 const char *rep_buffer,
+			 unsigned int rep_len)
+{
+	const struct nf_nat_l3proto *l3proto;
+	struct udphdr *udph;
+	int datalen, oldlen;
+
+	if (!skb_make_writable(skb, skb->len))
+		return 0;
+
+	if (rep_len > match_len &&
+	    rep_len - match_len > skb_tailroom(skb) &&
+	    !enlarge_skb(skb, rep_len - match_len))
+		return 0;
+
+	udph = (void *)skb->data + protoff;
+
+	oldlen = skb->len - protoff;
+	mangle_contents(skb, protoff + sizeof(*udph),
+			match_offset, match_len, rep_buffer, rep_len);
+
+	/* update the length of the UDP packet */
+	datalen = skb->len - protoff;
+	udph->len = htons(datalen);
+
+	/* fix udp checksum if udp checksum was previously calculated */
+	if (!udph->check && skb->ip_summed != CHECKSUM_PARTIAL)
+		return 1;
+
+	l3proto = __nf_nat_l3proto_find(nf_ct_l3num(ct));
+	l3proto->csum_recalc(skb, IPPROTO_UDP, udph, &udph->check,
+			     datalen, oldlen);
+
+	return 1;
+}
+EXPORT_SYMBOL(nf_nat_mangle_udp_packet);
+
+/* Adjust one found SACK option including checksum correction */
+static void
+sack_adjust(struct sk_buff *skb,
+	    struct tcphdr *tcph,
+	    unsigned int sackoff,
+	    unsigned int sackend,
+	    struct nf_nat_seq *natseq)
+{
+	while (sackoff < sackend) {
+		struct tcp_sack_block_wire *sack;
+		__be32 new_start_seq, new_end_seq;
+
+		sack = (void *)skb->data + sackoff;
+		if (after(ntohl(sack->start_seq) - natseq->offset_before,
+			  natseq->correction_pos))
+			new_start_seq = htonl(ntohl(sack->start_seq)
+					- natseq->offset_after);
+		else
+			new_start_seq = htonl(ntohl(sack->start_seq)
+					- natseq->offset_before);
+
+		if (after(ntohl(sack->end_seq) - natseq->offset_before,
+			  natseq->correction_pos))
+			new_end_seq = htonl(ntohl(sack->end_seq)
+				      - natseq->offset_after);
+		else
+			new_end_seq = htonl(ntohl(sack->end_seq)
+				      - natseq->offset_before);
+
+		pr_debug("sack_adjust: start_seq: %d->%d, end_seq: %d->%d\n",
+			 ntohl(sack->start_seq), new_start_seq,
+			 ntohl(sack->end_seq), new_end_seq);
+
+		inet_proto_csum_replace4(&tcph->check, skb,
+					 sack->start_seq, new_start_seq, 0);
+		inet_proto_csum_replace4(&tcph->check, skb,
+					 sack->end_seq, new_end_seq, 0);
+		sack->start_seq = new_start_seq;
+		sack->end_seq = new_end_seq;
+		sackoff += sizeof(*sack);
+	}
+}
+
+/* TCP SACK sequence number adjustment */
+static inline unsigned int
+nf_nat_sack_adjust(struct sk_buff *skb,
+		   unsigned int protoff,
+		   struct tcphdr *tcph,
+		   struct nf_conn *ct,
+		   enum ip_conntrack_info ctinfo)
+{
+	unsigned int dir, optoff, optend;
+	struct nf_conn_nat *nat = nfct_nat(ct);
+
+	optoff = protoff + sizeof(struct tcphdr);
+	optend = protoff + tcph->doff * 4;
+
+	if (!skb_make_writable(skb, optend))
+		return 0;
+
+	dir = CTINFO2DIR(ctinfo);
+
+	while (optoff < optend) {
+		/* Usually: option, length. */
+		unsigned char *op = skb->data + optoff;
+
+		switch (op[0]) {
+		case TCPOPT_EOL:
+			return 1;
+		case TCPOPT_NOP:
+			optoff++;
+			continue;
+		default:
+			/* no partial options */
+			if (optoff + 1 == optend ||
+			    optoff + op[1] > optend ||
+			    op[1] < 2)
+				return 0;
+			if (op[0] == TCPOPT_SACK &&
+			    op[1] >= 2+TCPOLEN_SACK_PERBLOCK &&
+			    ((op[1] - 2) % TCPOLEN_SACK_PERBLOCK) == 0)
+				sack_adjust(skb, tcph, optoff+2,
+					    optoff+op[1], &nat->seq[!dir]);
+			optoff += op[1];
+		}
+	}
+	return 1;
+}
+
+/* TCP sequence number adjustment.  Returns 1 on success, 0 on failure */
+int
+nf_nat_seq_adjust(struct sk_buff *skb,
+		  struct nf_conn *ct,
+		  enum ip_conntrack_info ctinfo,
+		  unsigned int protoff)
+{
+	struct tcphdr *tcph;
+	int dir;
+	__be32 newseq, newack;
+	s16 seqoff, ackoff;
+	struct nf_conn_nat *nat = nfct_nat(ct);
+	struct nf_nat_seq *this_way, *other_way;
+
+	dir = CTINFO2DIR(ctinfo);
+
+	this_way = &nat->seq[dir];
+	other_way = &nat->seq[!dir];
+
+	if (!skb_make_writable(skb, protoff + sizeof(*tcph)))
+		return 0;
+
+	tcph = (void *)skb->data + protoff;
+	if (after(ntohl(tcph->seq), this_way->correction_pos))
+		seqoff = this_way->offset_after;
+	else
+		seqoff = this_way->offset_before;
+
+	if (after(ntohl(tcph->ack_seq) - other_way->offset_before,
+		  other_way->correction_pos))
+		ackoff = other_way->offset_after;
+	else
+		ackoff = other_way->offset_before;
+
+	newseq = htonl(ntohl(tcph->seq) + seqoff);
+	newack = htonl(ntohl(tcph->ack_seq) - ackoff);
+
+	inet_proto_csum_replace4(&tcph->check, skb, tcph->seq, newseq, 0);
+	inet_proto_csum_replace4(&tcph->check, skb, tcph->ack_seq, newack, 0);
+
+	pr_debug("Adjusting sequence number from %u->%u, ack from %u->%u\n",
+		 ntohl(tcph->seq), ntohl(newseq), ntohl(tcph->ack_seq),
+		 ntohl(newack));
+
+	tcph->seq = newseq;
+	tcph->ack_seq = newack;
+
+	return nf_nat_sack_adjust(skb, protoff, tcph, ct, ctinfo);
+}
+
+/* Setup NAT on this expected conntrack so it follows master. */
+/* If we fail to get a free NAT slot, we'll get dropped on confirm */
+void nf_nat_follow_master(struct nf_conn *ct,
+			  struct nf_conntrack_expect *exp)
+{
+	struct nf_nat_range range;
+
+	/* This must be a fresh one. */
+	BUG_ON(ct->status & IPS_NAT_DONE_MASK);
+
+	/* Change src to where master sends to */
+	range.flags = NF_NAT_RANGE_MAP_IPS;
+	range.min_addr = range.max_addr
+		= ct->master->tuplehash[!exp->dir].tuple.dst.u3;
+	nf_nat_setup_info(ct, &range, NF_NAT_MANIP_SRC);
+
+	/* For DST manip, map port here to where it's expected. */
+	range.flags = (NF_NAT_RANGE_MAP_IPS | NF_NAT_RANGE_PROTO_SPECIFIED);
+	range.min_proto = range.max_proto = exp->saved_proto;
+	range.min_addr = range.max_addr
+		= ct->master->tuplehash[!exp->dir].tuple.src.u3;
+	nf_nat_setup_info(ct, &range, NF_NAT_MANIP_DST);
+}
+EXPORT_SYMBOL(nf_nat_follow_master);
diff --git a/net/netfilter/nf_nat_proto_common.c b/net/netfilter/nf_nat_proto_common.c
new file mode 100644
index 000000000000..9baaf734c142
--- /dev/null
+++ b/net/netfilter/nf_nat_proto_common.c
@@ -0,0 +1,112 @@
+/* (C) 1999-2001 Paul `Rusty' Russell
+ * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
+ * (C) 2008 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/types.h>
+#include <linux/random.h>
+#include <linux/netfilter.h>
+#include <linux/export.h>
+
+#include <net/netfilter/nf_nat.h>
+#include <net/netfilter/nf_nat_core.h>
+#include <net/netfilter/nf_nat_l3proto.h>
+#include <net/netfilter/nf_nat_l4proto.h>
+
+bool nf_nat_l4proto_in_range(const struct nf_conntrack_tuple *tuple,
+			     enum nf_nat_manip_type maniptype,
+			     const union nf_conntrack_man_proto *min,
+			     const union nf_conntrack_man_proto *max)
+{
+	__be16 port;
+
+	if (maniptype == NF_NAT_MANIP_SRC)
+		port = tuple->src.u.all;
+	else
+		port = tuple->dst.u.all;
+
+	return ntohs(port) >= ntohs(min->all) &&
+	       ntohs(port) <= ntohs(max->all);
+}
+EXPORT_SYMBOL_GPL(nf_nat_l4proto_in_range);
+
+void nf_nat_l4proto_unique_tuple(const struct nf_nat_l3proto *l3proto,
+				 struct nf_conntrack_tuple *tuple,
+				 const struct nf_nat_range *range,
+				 enum nf_nat_manip_type maniptype,
+				 const struct nf_conn *ct,
+				 u16 *rover)
+{
+	unsigned int range_size, min, i;
+	__be16 *portptr;
+	u_int16_t off;
+
+	if (maniptype == NF_NAT_MANIP_SRC)
+		portptr = &tuple->src.u.all;
+	else
+		portptr = &tuple->dst.u.all;
+
+	/* If no range specified... */
+	if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED)) {
+		/* If it's dst rewrite, can't change port */
+		if (maniptype == NF_NAT_MANIP_DST)
+			return;
+
+		if (ntohs(*portptr) < 1024) {
+			/* Loose convention: >> 512 is credential passing */
+			if (ntohs(*portptr) < 512) {
+				min = 1;
+				range_size = 511 - min + 1;
+			} else {
+				min = 600;
+				range_size = 1023 - min + 1;
+			}
+		} else {
+			min = 1024;
+			range_size = 65535 - 1024 + 1;
+		}
+	} else {
+		min = ntohs(range->min_proto.all);
+		range_size = ntohs(range->max_proto.all) - min + 1;
+	}
+
+	if (range->flags & NF_NAT_RANGE_PROTO_RANDOM)
+		off = l3proto->secure_port(tuple, maniptype == NF_NAT_MANIP_SRC
+						  ? tuple->dst.u.all
+						  : tuple->src.u.all);
+	else
+		off = *rover;
+
+	for (i = 0; ; ++off) {
+		*portptr = htons(min + off % range_size);
+		if (++i != range_size && nf_nat_used_tuple(tuple, ct))
+			continue;
+		if (!(range->flags & NF_NAT_RANGE_PROTO_RANDOM))
+			*rover = off;
+		return;
+	}
+	return;
+}
+EXPORT_SYMBOL_GPL(nf_nat_l4proto_unique_tuple);
+
+#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
+int nf_nat_l4proto_nlattr_to_range(struct nlattr *tb[],
+				   struct nf_nat_range *range)
+{
+	if (tb[CTA_PROTONAT_PORT_MIN]) {
+		range->min_proto.all = nla_get_be16(tb[CTA_PROTONAT_PORT_MIN]);
+		range->max_proto.all = range->min_proto.all;
+		range->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
+	}
+	if (tb[CTA_PROTONAT_PORT_MAX]) {
+		range->max_proto.all = nla_get_be16(tb[CTA_PROTONAT_PORT_MAX]);
+		range->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nf_nat_l4proto_nlattr_to_range);
+#endif
diff --git a/net/netfilter/nf_nat_proto_dccp.c b/net/netfilter/nf_nat_proto_dccp.c
new file mode 100644
index 000000000000..c8be2cdac0bf
--- /dev/null
+++ b/net/netfilter/nf_nat_proto_dccp.c
@@ -0,0 +1,116 @@
+/*
+ * DCCP NAT protocol helper
+ *
+ * Copyright (c) 2005, 2006, 2008 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/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/skbuff.h>
+#include <linux/dccp.h>
+
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_nat.h>
+#include <net/netfilter/nf_nat_l3proto.h>
+#include <net/netfilter/nf_nat_l4proto.h>
+
+static u_int16_t dccp_port_rover;
+
+static void
+dccp_unique_tuple(const struct nf_nat_l3proto *l3proto,
+		  struct nf_conntrack_tuple *tuple,
+		  const struct nf_nat_range *range,
+		  enum nf_nat_manip_type maniptype,
+		  const struct nf_conn *ct)
+{
+	nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
+				    &dccp_port_rover);
+}
+
+static bool
+dccp_manip_pkt(struct sk_buff *skb,
+	       const struct nf_nat_l3proto *l3proto,
+	       unsigned int iphdroff, unsigned int hdroff,
+	       const struct nf_conntrack_tuple *tuple,
+	       enum nf_nat_manip_type maniptype)
+{
+	struct dccp_hdr *hdr;
+	__be16 *portptr, oldport, newport;
+	int hdrsize = 8; /* DCCP connection tracking guarantees this much */
+
+	if (skb->len >= hdroff + sizeof(struct dccp_hdr))
+		hdrsize = sizeof(struct dccp_hdr);
+
+	if (!skb_make_writable(skb, hdroff + hdrsize))
+		return false;
+
+	hdr = (struct dccp_hdr *)(skb->data + hdroff);
+
+	if (maniptype == NF_NAT_MANIP_SRC) {
+		newport = tuple->src.u.dccp.port;
+		portptr = &hdr->dccph_sport;
+	} else {
+		newport = tuple->dst.u.dccp.port;
+		portptr = &hdr->dccph_dport;
+	}
+
+	oldport = *portptr;
+	*portptr = newport;
+
+	if (hdrsize < sizeof(*hdr))
+		return true;
+
+	l3proto->csum_update(skb, iphdroff, &hdr->dccph_checksum,
+			     tuple, maniptype);
+	inet_proto_csum_replace2(&hdr->dccph_checksum, skb, oldport, newport,
+				 0);
+	return true;
+}
+
+static const struct nf_nat_l4proto nf_nat_l4proto_dccp = {
+	.l4proto		= IPPROTO_DCCP,
+	.manip_pkt		= dccp_manip_pkt,
+	.in_range		= nf_nat_l4proto_in_range,
+	.unique_tuple		= dccp_unique_tuple,
+#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
+	.nlattr_to_range	= nf_nat_l4proto_nlattr_to_range,
+#endif
+};
+
+static int __init nf_nat_proto_dccp_init(void)
+{
+	int err;
+
+	err = nf_nat_l4proto_register(NFPROTO_IPV4, &nf_nat_l4proto_dccp);
+	if (err < 0)
+		goto err1;
+	err = nf_nat_l4proto_register(NFPROTO_IPV6, &nf_nat_l4proto_dccp);
+	if (err < 0)
+		goto err2;
+	return 0;
+
+err2:
+	nf_nat_l4proto_unregister(NFPROTO_IPV4, &nf_nat_l4proto_dccp);
+err1:
+	return err;
+}
+
+static void __exit nf_nat_proto_dccp_fini(void)
+{
+	nf_nat_l4proto_unregister(NFPROTO_IPV6, &nf_nat_l4proto_dccp);
+	nf_nat_l4proto_unregister(NFPROTO_IPV4, &nf_nat_l4proto_dccp);
+
+}
+
+module_init(nf_nat_proto_dccp_init);
+module_exit(nf_nat_proto_dccp_fini);
+
+MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
+MODULE_DESCRIPTION("DCCP NAT protocol helper");
+MODULE_LICENSE("GPL");
diff --git a/net/netfilter/nf_nat_proto_sctp.c b/net/netfilter/nf_nat_proto_sctp.c
new file mode 100644
index 000000000000..e64faa5ca893
--- /dev/null
+++ b/net/netfilter/nf_nat_proto_sctp.c
@@ -0,0 +1,103 @@
+/*
+ * Copyright (c) 2008 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/types.h>
+#include <linux/init.h>
+#include <linux/sctp.h>
+#include <linux/module.h>
+#include <net/sctp/checksum.h>
+
+#include <net/netfilter/nf_nat_l4proto.h>
+
+static u_int16_t nf_sctp_port_rover;
+
+static void
+sctp_unique_tuple(const struct nf_nat_l3proto *l3proto,
+		  struct nf_conntrack_tuple *tuple,
+		  const struct nf_nat_range *range,
+		  enum nf_nat_manip_type maniptype,
+		  const struct nf_conn *ct)
+{
+	nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
+				    &nf_sctp_port_rover);
+}
+
+static bool
+sctp_manip_pkt(struct sk_buff *skb,
+	       const struct nf_nat_l3proto *l3proto,
+	       unsigned int iphdroff, unsigned int hdroff,
+	       const struct nf_conntrack_tuple *tuple,
+	       enum nf_nat_manip_type maniptype)
+{
+	struct sk_buff *frag;
+	sctp_sctphdr_t *hdr;
+	__be32 crc32;
+
+	if (!skb_make_writable(skb, hdroff + sizeof(*hdr)))
+		return false;
+
+	hdr = (struct sctphdr *)(skb->data + hdroff);
+
+	if (maniptype == NF_NAT_MANIP_SRC) {
+		/* Get rid of src port */
+		hdr->source = tuple->src.u.sctp.port;
+	} else {
+		/* Get rid of dst port */
+		hdr->dest = tuple->dst.u.sctp.port;
+	}
+
+	crc32 = sctp_start_cksum((u8 *)hdr, skb_headlen(skb) - hdroff);
+	skb_walk_frags(skb, frag)
+		crc32 = sctp_update_cksum((u8 *)frag->data, skb_headlen(frag),
+					  crc32);
+	crc32 = sctp_end_cksum(crc32);
+	hdr->checksum = crc32;
+
+	return true;
+}
+
+static const struct nf_nat_l4proto nf_nat_l4proto_sctp = {
+	.l4proto		= IPPROTO_SCTP,
+	.manip_pkt		= sctp_manip_pkt,
+	.in_range		= nf_nat_l4proto_in_range,
+	.unique_tuple		= sctp_unique_tuple,
+#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
+	.nlattr_to_range	= nf_nat_l4proto_nlattr_to_range,
+#endif
+};
+
+static int __init nf_nat_proto_sctp_init(void)
+{
+	int err;
+
+	err = nf_nat_l4proto_register(NFPROTO_IPV4, &nf_nat_l4proto_sctp);
+	if (err < 0)
+		goto err1;
+	err = nf_nat_l4proto_register(NFPROTO_IPV6, &nf_nat_l4proto_sctp);
+	if (err < 0)
+		goto err2;
+	return 0;
+
+err2:
+	nf_nat_l4proto_unregister(NFPROTO_IPV4, &nf_nat_l4proto_sctp);
+err1:
+	return err;
+}
+
+static void __exit nf_nat_proto_sctp_exit(void)
+{
+	nf_nat_l4proto_unregister(NFPROTO_IPV6, &nf_nat_l4proto_sctp);
+	nf_nat_l4proto_unregister(NFPROTO_IPV4, &nf_nat_l4proto_sctp);
+}
+
+module_init(nf_nat_proto_sctp_init);
+module_exit(nf_nat_proto_sctp_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("SCTP NAT protocol helper");
+MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
diff --git a/net/netfilter/nf_nat_proto_tcp.c b/net/netfilter/nf_nat_proto_tcp.c
new file mode 100644
index 000000000000..83ec8a6e4c36
--- /dev/null
+++ b/net/netfilter/nf_nat_proto_tcp.c
@@ -0,0 +1,85 @@
+/* (C) 1999-2001 Paul `Rusty' Russell
+ * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
+ *
+ * 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/types.h>
+#include <linux/init.h>
+#include <linux/export.h>
+#include <linux/tcp.h>
+
+#include <linux/netfilter.h>
+#include <linux/netfilter/nfnetlink_conntrack.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>
+
+static u16 tcp_port_rover;
+
+static void
+tcp_unique_tuple(const struct nf_nat_l3proto *l3proto,
+		 struct nf_conntrack_tuple *tuple,
+		 const struct nf_nat_range *range,
+		 enum nf_nat_manip_type maniptype,
+		 const struct nf_conn *ct)
+{
+	nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
+				    &tcp_port_rover);
+}
+
+static bool
+tcp_manip_pkt(struct sk_buff *skb,
+	      const struct nf_nat_l3proto *l3proto,
+	      unsigned int iphdroff, unsigned int hdroff,
+	      const struct nf_conntrack_tuple *tuple,
+	      enum nf_nat_manip_type maniptype)
+{
+	struct tcphdr *hdr;
+	__be16 *portptr, newport, oldport;
+	int hdrsize = 8; /* TCP connection tracking guarantees this much */
+
+	/* this could be a inner header returned in icmp packet; in such
+	   cases we cannot update the checksum field since it is outside of
+	   the 8 bytes of transport layer headers we are guaranteed */
+	if (skb->len >= hdroff + sizeof(struct tcphdr))
+		hdrsize = sizeof(struct tcphdr);
+
+	if (!skb_make_writable(skb, hdroff + hdrsize))
+		return false;
+
+	hdr = (struct tcphdr *)(skb->data + hdroff);
+
+	if (maniptype == NF_NAT_MANIP_SRC) {
+		/* Get rid of src port */
+		newport = tuple->src.u.tcp.port;
+		portptr = &hdr->source;
+	} else {
+		/* Get rid of dst port */
+		newport = tuple->dst.u.tcp.port;
+		portptr = &hdr->dest;
+	}
+
+	oldport = *portptr;
+	*portptr = newport;
+
+	if (hdrsize < sizeof(*hdr))
+		return true;
+
+	l3proto->csum_update(skb, iphdroff, &hdr->check, tuple, maniptype);
+	inet_proto_csum_replace2(&hdr->check, skb, oldport, newport, 0);
+	return true;
+}
+
+const struct nf_nat_l4proto nf_nat_l4proto_tcp = {
+	.l4proto		= IPPROTO_TCP,
+	.manip_pkt		= tcp_manip_pkt,
+	.in_range		= nf_nat_l4proto_in_range,
+	.unique_tuple		= tcp_unique_tuple,
+#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
+	.nlattr_to_range	= nf_nat_l4proto_nlattr_to_range,
+#endif
+};
diff --git a/net/netfilter/nf_nat_proto_udp.c b/net/netfilter/nf_nat_proto_udp.c
new file mode 100644
index 000000000000..7df613fb34a2
--- /dev/null
+++ b/net/netfilter/nf_nat_proto_udp.c
@@ -0,0 +1,76 @@
+/* (C) 1999-2001 Paul `Rusty' Russell
+ * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
+ *
+ * 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/types.h>
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/udp.h>
+
+#include <linux/netfilter.h>
+#include <net/netfilter/nf_nat.h>
+#include <net/netfilter/nf_nat_core.h>
+#include <net/netfilter/nf_nat_l3proto.h>
+#include <net/netfilter/nf_nat_l4proto.h>
+
+static u16 udp_port_rover;
+
+static void
+udp_unique_tuple(const struct nf_nat_l3proto *l3proto,
+		 struct nf_conntrack_tuple *tuple,
+		 const struct nf_nat_range *range,
+		 enum nf_nat_manip_type maniptype,
+		 const struct nf_conn *ct)
+{
+	nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
+				    &udp_port_rover);
+}
+
+static bool
+udp_manip_pkt(struct sk_buff *skb,
+	      const struct nf_nat_l3proto *l3proto,
+	      unsigned int iphdroff, unsigned int hdroff,
+	      const struct nf_conntrack_tuple *tuple,
+	      enum nf_nat_manip_type maniptype)
+{
+	struct udphdr *hdr;
+	__be16 *portptr, newport;
+
+	if (!skb_make_writable(skb, hdroff + sizeof(*hdr)))
+		return false;
+	hdr = (struct udphdr *)(skb->data + hdroff);
+
+	if (maniptype == NF_NAT_MANIP_SRC) {
+		/* Get rid of src port */
+		newport = tuple->src.u.udp.port;
+		portptr = &hdr->source;
+	} else {
+		/* Get rid of dst port */
+		newport = tuple->dst.u.udp.port;
+		portptr = &hdr->dest;
+	}
+	if (hdr->check || skb->ip_summed == CHECKSUM_PARTIAL) {
+		l3proto->csum_update(skb, iphdroff, &hdr->check,
+				     tuple, maniptype);
+		inet_proto_csum_replace2(&hdr->check, skb, *portptr, newport,
+					 0);
+		if (!hdr->check)
+			hdr->check = CSUM_MANGLED_0;
+	}
+	*portptr = newport;
+	return true;
+}
+
+const struct nf_nat_l4proto nf_nat_l4proto_udp = {
+	.l4proto		= IPPROTO_UDP,
+	.manip_pkt		= udp_manip_pkt,
+	.in_range		= nf_nat_l4proto_in_range,
+	.unique_tuple		= udp_unique_tuple,
+#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
+	.nlattr_to_range	= nf_nat_l4proto_nlattr_to_range,
+#endif
+};
diff --git a/net/netfilter/nf_nat_proto_udplite.c b/net/netfilter/nf_nat_proto_udplite.c
new file mode 100644
index 000000000000..776a0d1317b1
--- /dev/null
+++ b/net/netfilter/nf_nat_proto_udplite.c
@@ -0,0 +1,106 @@
+/* (C) 1999-2001 Paul `Rusty' Russell
+ * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
+ * (C) 2008 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/types.h>
+#include <linux/init.h>
+#include <linux/udp.h>
+
+#include <linux/netfilter.h>
+#include <linux/module.h>
+#include <net/netfilter/nf_nat.h>
+#include <net/netfilter/nf_nat_l3proto.h>
+#include <net/netfilter/nf_nat_l4proto.h>
+
+static u16 udplite_port_rover;
+
+static void
+udplite_unique_tuple(const struct nf_nat_l3proto *l3proto,
+		     struct nf_conntrack_tuple *tuple,
+		     const struct nf_nat_range *range,
+		     enum nf_nat_manip_type maniptype,
+		     const struct nf_conn *ct)
+{
+	nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
+				    &udplite_port_rover);
+}
+
+static bool
+udplite_manip_pkt(struct sk_buff *skb,
+		  const struct nf_nat_l3proto *l3proto,
+		  unsigned int iphdroff, unsigned int hdroff,
+		  const struct nf_conntrack_tuple *tuple,
+		  enum nf_nat_manip_type maniptype)
+{
+	struct udphdr *hdr;
+	__be16 *portptr, newport;
+
+	if (!skb_make_writable(skb, hdroff + sizeof(*hdr)))
+		return false;
+
+	hdr = (struct udphdr *)(skb->data + hdroff);
+
+	if (maniptype == NF_NAT_MANIP_SRC) {
+		/* Get rid of source port */
+		newport = tuple->src.u.udp.port;
+		portptr = &hdr->source;
+	} else {
+		/* Get rid of dst port */
+		newport = tuple->dst.u.udp.port;
+		portptr = &hdr->dest;
+	}
+
+	l3proto->csum_update(skb, iphdroff, &hdr->check, tuple, maniptype);
+	inet_proto_csum_replace2(&hdr->check, skb, *portptr, newport, 0);
+	if (!hdr->check)
+		hdr->check = CSUM_MANGLED_0;
+
+	*portptr = newport;
+	return true;
+}
+
+static const struct nf_nat_l4proto nf_nat_l4proto_udplite = {
+	.l4proto		= IPPROTO_UDPLITE,
+	.manip_pkt		= udplite_manip_pkt,
+	.in_range		= nf_nat_l4proto_in_range,
+	.unique_tuple		= udplite_unique_tuple,
+#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
+	.nlattr_to_range	= nf_nat_l4proto_nlattr_to_range,
+#endif
+};
+
+static int __init nf_nat_proto_udplite_init(void)
+{
+	int err;
+
+	err = nf_nat_l4proto_register(NFPROTO_IPV4, &nf_nat_l4proto_udplite);
+	if (err < 0)
+		goto err1;
+	err = nf_nat_l4proto_register(NFPROTO_IPV6, &nf_nat_l4proto_udplite);
+	if (err < 0)
+		goto err2;
+	return 0;
+
+err2:
+	nf_nat_l4proto_unregister(NFPROTO_IPV4, &nf_nat_l4proto_udplite);
+err1:
+	return err;
+}
+
+static void __exit nf_nat_proto_udplite_fini(void)
+{
+	nf_nat_l4proto_unregister(NFPROTO_IPV6, &nf_nat_l4proto_udplite);
+	nf_nat_l4proto_unregister(NFPROTO_IPV4, &nf_nat_l4proto_udplite);
+}
+
+module_init(nf_nat_proto_udplite_init);
+module_exit(nf_nat_proto_udplite_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("UDP-Lite NAT protocol helper");
+MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
diff --git a/net/netfilter/nf_nat_proto_unknown.c b/net/netfilter/nf_nat_proto_unknown.c
new file mode 100644
index 000000000000..6e494d584412
--- /dev/null
+++ b/net/netfilter/nf_nat_proto_unknown.c
@@ -0,0 +1,54 @@
+/* The "unknown" protocol.  This is what is used for protocols we
+ * don't understand.  It's returned by ip_ct_find_proto().
+ */
+
+/* (C) 1999-2001 Paul `Rusty' Russell
+ * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
+ *
+ * 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/types.h>
+#include <linux/init.h>
+
+#include <linux/netfilter.h>
+#include <net/netfilter/nf_nat.h>
+#include <net/netfilter/nf_nat_l4proto.h>
+
+static bool unknown_in_range(const struct nf_conntrack_tuple *tuple,
+			     enum nf_nat_manip_type manip_type,
+			     const union nf_conntrack_man_proto *min,
+			     const union nf_conntrack_man_proto *max)
+{
+	return true;
+}
+
+static void unknown_unique_tuple(const struct nf_nat_l3proto *l3proto,
+				 struct nf_conntrack_tuple *tuple,
+				 const struct nf_nat_range *range,
+				 enum nf_nat_manip_type maniptype,
+				 const struct nf_conn *ct)
+{
+	/* Sorry: we can't help you; if it's not unique, we can't frob
+	 * anything.
+	 */
+	return;
+}
+
+static bool
+unknown_manip_pkt(struct sk_buff *skb,
+		  const struct nf_nat_l3proto *l3proto,
+		  unsigned int iphdroff, unsigned int hdroff,
+		  const struct nf_conntrack_tuple *tuple,
+		  enum nf_nat_manip_type maniptype)
+{
+	return true;
+}
+
+const struct nf_nat_l4proto nf_nat_l4proto_unknown = {
+	.manip_pkt		= unknown_manip_pkt,
+	.in_range		= unknown_in_range,
+	.unique_tuple		= unknown_unique_tuple,
+};
diff --git a/net/netfilter/xt_nat.c b/net/netfilter/xt_nat.c
new file mode 100644
index 000000000000..7521368a6034
--- /dev/null
+++ b/net/netfilter/xt_nat.c
@@ -0,0 +1,167 @@
+/*
+ * (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/skbuff.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/x_tables.h>
+#include <net/netfilter/nf_nat_core.h>
+
+static int xt_nat_checkentry_v0(const struct xt_tgchk_param *par)
+{
+	const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
+
+	if (mr->rangesize != 1) {
+		pr_info("%s: multiple ranges no longer supported\n",
+			par->target->name);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static void xt_nat_convert_range(struct nf_nat_range *dst,
+				 const struct nf_nat_ipv4_range *src)
+{
+	memset(&dst->min_addr, 0, sizeof(dst->min_addr));
+	memset(&dst->max_addr, 0, sizeof(dst->max_addr));
+
+	dst->flags	 = src->flags;
+	dst->min_addr.ip = src->min_ip;
+	dst->max_addr.ip = src->max_ip;
+	dst->min_proto	 = src->min;
+	dst->max_proto	 = src->max;
+}
+
+static unsigned int
+xt_snat_target_v0(struct sk_buff *skb, const struct xt_action_param *par)
+{
+	const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
+	struct nf_nat_range range;
+	enum ip_conntrack_info ctinfo;
+	struct nf_conn *ct;
+
+	ct = nf_ct_get(skb, &ctinfo);
+	NF_CT_ASSERT(ct != NULL &&
+		     (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED ||
+		      ctinfo == IP_CT_RELATED_REPLY));
+
+	xt_nat_convert_range(&range, &mr->range[0]);
+	return nf_nat_setup_info(ct, &range, NF_NAT_MANIP_SRC);
+}
+
+static unsigned int
+xt_dnat_target_v0(struct sk_buff *skb, const struct xt_action_param *par)
+{
+	const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
+	struct nf_nat_range range;
+	enum ip_conntrack_info ctinfo;
+	struct nf_conn *ct;
+
+	ct = nf_ct_get(skb, &ctinfo);
+	NF_CT_ASSERT(ct != NULL &&
+		     (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED));
+
+	xt_nat_convert_range(&range, &mr->range[0]);
+	return nf_nat_setup_info(ct, &range, NF_NAT_MANIP_DST);
+}
+
+static unsigned int
+xt_snat_target_v1(struct sk_buff *skb, const struct xt_action_param *par)
+{
+	const struct nf_nat_range *range = par->targinfo;
+	enum ip_conntrack_info ctinfo;
+	struct nf_conn *ct;
+
+	ct = nf_ct_get(skb, &ctinfo);
+	NF_CT_ASSERT(ct != NULL &&
+		     (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED ||
+		      ctinfo == IP_CT_RELATED_REPLY));
+
+	return nf_nat_setup_info(ct, range, NF_NAT_MANIP_SRC);
+}
+
+static unsigned int
+xt_dnat_target_v1(struct sk_buff *skb, const struct xt_action_param *par)
+{
+	const struct nf_nat_range *range = par->targinfo;
+	enum ip_conntrack_info ctinfo;
+	struct nf_conn *ct;
+
+	ct = nf_ct_get(skb, &ctinfo);
+	NF_CT_ASSERT(ct != NULL &&
+		     (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED));
+
+	return nf_nat_setup_info(ct, range, NF_NAT_MANIP_DST);
+}
+
+static struct xt_target xt_nat_target_reg[] __read_mostly = {
+	{
+		.name		= "SNAT",
+		.revision	= 0,
+		.checkentry	= xt_nat_checkentry_v0,
+		.target		= xt_snat_target_v0,
+		.targetsize	= sizeof(struct nf_nat_ipv4_multi_range_compat),
+		.family		= NFPROTO_IPV4,
+		.table		= "nat",
+		.hooks		= (1 << NF_INET_POST_ROUTING) |
+				  (1 << NF_INET_LOCAL_OUT),
+		.me		= THIS_MODULE,
+	},
+	{
+		.name		= "DNAT",
+		.revision	= 0,
+		.checkentry	= xt_nat_checkentry_v0,
+		.target		= xt_dnat_target_v0,
+		.targetsize	= sizeof(struct nf_nat_ipv4_multi_range_compat),
+		.family		= NFPROTO_IPV4,
+		.table		= "nat",
+		.hooks		= (1 << NF_INET_PRE_ROUTING) |
+				  (1 << NF_INET_LOCAL_IN),
+		.me		= THIS_MODULE,
+	},
+	{
+		.name		= "SNAT",
+		.revision	= 1,
+		.target		= xt_snat_target_v1,
+		.targetsize	= sizeof(struct nf_nat_range),
+		.table		= "nat",
+		.hooks		= (1 << NF_INET_POST_ROUTING) |
+				  (1 << NF_INET_LOCAL_OUT),
+		.me		= THIS_MODULE,
+	},
+	{
+		.name		= "DNAT",
+		.revision	= 1,
+		.target		= xt_dnat_target_v1,
+		.targetsize	= sizeof(struct nf_nat_range),
+		.table		= "nat",
+		.hooks		= (1 << NF_INET_PRE_ROUTING) |
+				  (1 << NF_INET_LOCAL_IN),
+		.me		= THIS_MODULE,
+	},
+};
+
+static int __init xt_nat_init(void)
+{
+	return xt_register_targets(xt_nat_target_reg,
+				   ARRAY_SIZE(xt_nat_target_reg));
+}
+
+static void __exit xt_nat_exit(void)
+{
+	xt_unregister_targets(xt_nat_target_reg, ARRAY_SIZE(xt_nat_target_reg));
+}
+
+module_init(xt_nat_init);
+module_exit(xt_nat_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("ipt_SNAT");
+MODULE_ALIAS("ipt_DNAT");