diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
new file mode 100644
index 0000000..1189fd5
--- /dev/null
+++ b/net/openvswitch/conntrack.c
@@ -0,0 +1,454 @@
+/*
+ * Copyright (c) 2015 Nicira, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/openvswitch.h>
+#include <net/ip.h>
+#include <net/netfilter/nf_conntrack_core.h>
+#include <net/netfilter/nf_conntrack_zones.h>
+#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
+
+#include "datapath.h"
+#include "conntrack.h"
+#include "flow.h"
+#include "flow_netlink.h"
+
+struct ovs_ct_len_tbl {
+	size_t maxlen;
+	size_t minlen;
+};
+
+/* Conntrack action context for execution. */
+struct ovs_conntrack_info {
+	struct nf_conntrack_zone zone;
+	struct nf_conn *ct;
+	u32 flags;
+	u16 family;
+};
+
+static u16 key_to_nfproto(const struct sw_flow_key *key)
+{
+	switch (ntohs(key->eth.type)) {
+	case ETH_P_IP:
+		return NFPROTO_IPV4;
+	case ETH_P_IPV6:
+		return NFPROTO_IPV6;
+	default:
+		return NFPROTO_UNSPEC;
+	}
+}
+
+/* Map SKB connection state into the values used by flow definition. */
+static u8 ovs_ct_get_state(enum ip_conntrack_info ctinfo)
+{
+	u8 ct_state = OVS_CS_F_TRACKED;
+
+	switch (ctinfo) {
+	case IP_CT_ESTABLISHED_REPLY:
+	case IP_CT_RELATED_REPLY:
+	case IP_CT_NEW_REPLY:
+		ct_state |= OVS_CS_F_REPLY_DIR;
+		break;
+	default:
+		break;
+	}
+
+	switch (ctinfo) {
+	case IP_CT_ESTABLISHED:
+	case IP_CT_ESTABLISHED_REPLY:
+		ct_state |= OVS_CS_F_ESTABLISHED;
+		break;
+	case IP_CT_RELATED:
+	case IP_CT_RELATED_REPLY:
+		ct_state |= OVS_CS_F_RELATED;
+		break;
+	case IP_CT_NEW:
+	case IP_CT_NEW_REPLY:
+		ct_state |= OVS_CS_F_NEW;
+		break;
+	default:
+		break;
+	}
+
+	return ct_state;
+}
+
+static void __ovs_ct_update_key(struct sw_flow_key *key, u8 state,
+				const struct nf_conntrack_zone *zone)
+{
+	key->ct.state = state;
+	key->ct.zone = zone->id;
+}
+
+/* Update 'key' based on skb->nfct. If 'post_ct' is true, then OVS has
+ * previously sent the packet to conntrack via the ct action.
+ */
+static void ovs_ct_update_key(const struct sk_buff *skb,
+			      struct sw_flow_key *key, bool post_ct)
+{
+	const struct nf_conntrack_zone *zone = &nf_ct_zone_dflt;
+	enum ip_conntrack_info ctinfo;
+	struct nf_conn *ct;
+	u8 state = 0;
+
+	ct = nf_ct_get(skb, &ctinfo);
+	if (ct) {
+		state = ovs_ct_get_state(ctinfo);
+		if (ct->master)
+			state |= OVS_CS_F_RELATED;
+		zone = nf_ct_zone(ct);
+	} else if (post_ct) {
+		state = OVS_CS_F_TRACKED | OVS_CS_F_INVALID;
+	}
+	__ovs_ct_update_key(key, state, zone);
+}
+
+void ovs_ct_fill_key(const struct sk_buff *skb, struct sw_flow_key *key)
+{
+	ovs_ct_update_key(skb, key, false);
+}
+
+int ovs_ct_put_key(const struct sw_flow_key *key, struct sk_buff *skb)
+{
+	if (nla_put_u8(skb, OVS_KEY_ATTR_CT_STATE, key->ct.state))
+		return -EMSGSIZE;
+
+	if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) &&
+	    nla_put_u16(skb, OVS_KEY_ATTR_CT_ZONE, key->ct.zone))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+static int handle_fragments(struct net *net, struct sw_flow_key *key,
+			    u16 zone, struct sk_buff *skb)
+{
+	struct ovs_skb_cb ovs_cb = *OVS_CB(skb);
+
+	if (key->eth.type == htons(ETH_P_IP)) {
+		enum ip_defrag_users user = IP_DEFRAG_CONNTRACK_IN + zone;
+		int err;
+
+		memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
+		err = ip_defrag(skb, user);
+		if (err)
+			return err;
+
+		ovs_cb.mru = IPCB(skb)->frag_max_size;
+	} else if (key->eth.type == htons(ETH_P_IPV6)) {
+#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
+		enum ip6_defrag_users user = IP6_DEFRAG_CONNTRACK_IN + zone;
+		struct sk_buff *reasm;
+
+		memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
+		reasm = nf_ct_frag6_gather(skb, user);
+		if (!reasm)
+			return -EINPROGRESS;
+
+		if (skb == reasm)
+			return -EINVAL;
+
+		key->ip.proto = ipv6_hdr(reasm)->nexthdr;
+		skb_morph(skb, reasm);
+		consume_skb(reasm);
+		ovs_cb.mru = IP6CB(skb)->frag_max_size;
+#else
+		return -EPFNOSUPPORT;
+#endif
+	} else {
+		return -EPFNOSUPPORT;
+	}
+
+	key->ip.frag = OVS_FRAG_TYPE_NONE;
+	skb_clear_hash(skb);
+	skb->ignore_df = 1;
+	*OVS_CB(skb) = ovs_cb;
+
+	return 0;
+}
+
+static struct nf_conntrack_expect *
+ovs_ct_expect_find(struct net *net, const struct nf_conntrack_zone *zone,
+		   u16 proto, const struct sk_buff *skb)
+{
+	struct nf_conntrack_tuple tuple;
+
+	if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb), proto, &tuple))
+		return NULL;
+	return __nf_ct_expect_find(net, zone, &tuple);
+}
+
+/* Determine whether skb->nfct is equal to the result of conntrack lookup. */
+static bool skb_nfct_cached(const struct net *net, const struct sk_buff *skb,
+			    const struct ovs_conntrack_info *info)
+{
+	enum ip_conntrack_info ctinfo;
+	struct nf_conn *ct;
+
+	ct = nf_ct_get(skb, &ctinfo);
+	if (!ct)
+		return false;
+	if (!net_eq(net, read_pnet(&ct->ct_net)))
+		return false;
+	if (!nf_ct_zone_equal_any(info->ct, nf_ct_zone(ct)))
+		return false;
+
+	return true;
+}
+
+static int __ovs_ct_lookup(struct net *net, const struct sw_flow_key *key,
+			   const struct ovs_conntrack_info *info,
+			   struct sk_buff *skb)
+{
+	/* If we are recirculating packets to match on conntrack fields and
+	 * committing with a separate conntrack action,  then we don't need to
+	 * actually run the packet through conntrack twice unless it's for a
+	 * different zone.
+	 */
+	if (!skb_nfct_cached(net, skb, info)) {
+		struct nf_conn *tmpl = info->ct;
+
+		/* Associate skb with specified zone. */
+		if (tmpl) {
+			if (skb->nfct)
+				nf_conntrack_put(skb->nfct);
+			nf_conntrack_get(&tmpl->ct_general);
+			skb->nfct = &tmpl->ct_general;
+			skb->nfctinfo = IP_CT_NEW;
+		}
+
+		if (nf_conntrack_in(net, info->family, NF_INET_PRE_ROUTING,
+				    skb) != NF_ACCEPT)
+			return -ENOENT;
+	}
+
+	return 0;
+}
+
+/* Lookup connection and read fields into key. */
+static int ovs_ct_lookup(struct net *net, struct sw_flow_key *key,
+			 const struct ovs_conntrack_info *info,
+			 struct sk_buff *skb)
+{
+	struct nf_conntrack_expect *exp;
+
+	exp = ovs_ct_expect_find(net, &info->zone, info->family, skb);
+	if (exp) {
+		u8 state;
+
+		state = OVS_CS_F_TRACKED | OVS_CS_F_NEW | OVS_CS_F_RELATED;
+		__ovs_ct_update_key(key, state, &info->zone);
+	} else {
+		int err;
+
+		err = __ovs_ct_lookup(net, key, info, skb);
+		if (err)
+			return err;
+
+		ovs_ct_update_key(skb, key, true);
+	}
+
+	return 0;
+}
+
+/* Lookup connection and confirm if unconfirmed. */
+static int ovs_ct_commit(struct net *net, struct sw_flow_key *key,
+			 const struct ovs_conntrack_info *info,
+			 struct sk_buff *skb)
+{
+	u8 state;
+	int err;
+
+	state = key->ct.state;
+	if (key->ct.zone == info->zone.id &&
+	    ((state & OVS_CS_F_TRACKED) && !(state & OVS_CS_F_NEW))) {
+		/* Previous lookup has shown that this connection is already
+		 * tracked and committed. Skip committing.
+		 */
+		return 0;
+	}
+
+	err = __ovs_ct_lookup(net, key, info, skb);
+	if (err)
+		return err;
+	if (nf_conntrack_confirm(skb) != NF_ACCEPT)
+		return -EINVAL;
+
+	ovs_ct_update_key(skb, key, true);
+
+	return 0;
+}
+
+int ovs_ct_execute(struct net *net, struct sk_buff *skb,
+		   struct sw_flow_key *key,
+		   const struct ovs_conntrack_info *info)
+{
+	int nh_ofs;
+	int err;
+
+	/* The conntrack module expects to be working at L3. */
+	nh_ofs = skb_network_offset(skb);
+	skb_pull(skb, nh_ofs);
+
+	if (key->ip.frag != OVS_FRAG_TYPE_NONE) {
+		err = handle_fragments(net, key, info->zone.id, skb);
+		if (err)
+			return err;
+	}
+
+	if (info->flags & OVS_CT_F_COMMIT)
+		err = ovs_ct_commit(net, key, info, skb);
+	else
+		err = ovs_ct_lookup(net, key, info, skb);
+
+	skb_push(skb, nh_ofs);
+	return err;
+}
+
+static const struct ovs_ct_len_tbl ovs_ct_attr_lens[OVS_CT_ATTR_MAX + 1] = {
+	[OVS_CT_ATTR_FLAGS]	= { .minlen = sizeof(u32),
+				    .maxlen = sizeof(u32) },
+	[OVS_CT_ATTR_ZONE]	= { .minlen = sizeof(u16),
+				    .maxlen = sizeof(u16) },
+};
+
+static int parse_ct(const struct nlattr *attr, struct ovs_conntrack_info *info,
+		    bool log)
+{
+	struct nlattr *a;
+	int rem;
+
+	nla_for_each_nested(a, attr, rem) {
+		int type = nla_type(a);
+		int maxlen = ovs_ct_attr_lens[type].maxlen;
+		int minlen = ovs_ct_attr_lens[type].minlen;
+
+		if (type > OVS_CT_ATTR_MAX) {
+			OVS_NLERR(log,
+				  "Unknown conntrack attr (type=%d, max=%d)",
+				  type, OVS_CT_ATTR_MAX);
+			return -EINVAL;
+		}
+		if (nla_len(a) < minlen || nla_len(a) > maxlen) {
+			OVS_NLERR(log,
+				  "Conntrack attr type has unexpected length (type=%d, length=%d, expected=%d)",
+				  type, nla_len(a), maxlen);
+			return -EINVAL;
+		}
+
+		switch (type) {
+		case OVS_CT_ATTR_FLAGS:
+			info->flags = nla_get_u32(a);
+			break;
+#ifdef CONFIG_NF_CONNTRACK_ZONES
+		case OVS_CT_ATTR_ZONE:
+			info->zone.id = nla_get_u16(a);
+			break;
+#endif
+		default:
+			OVS_NLERR(log, "Unknown conntrack attr (%d)",
+				  type);
+			return -EINVAL;
+		}
+	}
+
+	if (rem > 0) {
+		OVS_NLERR(log, "Conntrack attr has %d unknown bytes", rem);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+bool ovs_ct_verify(enum ovs_key_attr attr)
+{
+	if (attr == OVS_KEY_ATTR_CT_STATE)
+		return true;
+	if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) &&
+	    attr == OVS_KEY_ATTR_CT_ZONE)
+		return true;
+
+	return false;
+}
+
+int ovs_ct_copy_action(struct net *net, const struct nlattr *attr,
+		       const struct sw_flow_key *key,
+		       struct sw_flow_actions **sfa,  bool log)
+{
+	struct ovs_conntrack_info ct_info;
+	u16 family;
+	int err;
+
+	family = key_to_nfproto(key);
+	if (family == NFPROTO_UNSPEC) {
+		OVS_NLERR(log, "ct family unspecified");
+		return -EINVAL;
+	}
+
+	memset(&ct_info, 0, sizeof(ct_info));
+	ct_info.family = family;
+
+	nf_ct_zone_init(&ct_info.zone, NF_CT_DEFAULT_ZONE_ID,
+			NF_CT_DEFAULT_ZONE_DIR, 0);
+
+	err = parse_ct(attr, &ct_info, log);
+	if (err)
+		return err;
+
+	/* Set up template for tracking connections in specific zones. */
+	ct_info.ct = nf_ct_tmpl_alloc(net, &ct_info.zone, GFP_KERNEL);
+	if (!ct_info.ct) {
+		OVS_NLERR(log, "Failed to allocate conntrack template");
+		return -ENOMEM;
+	}
+
+	err = ovs_nla_add_action(sfa, OVS_ACTION_ATTR_CT, &ct_info,
+				 sizeof(ct_info), log);
+	if (err)
+		goto err_free_ct;
+
+	__set_bit(IPS_CONFIRMED_BIT, &ct_info.ct->status);
+	nf_conntrack_get(&ct_info.ct->ct_general);
+	return 0;
+err_free_ct:
+	nf_conntrack_free(ct_info.ct);
+	return err;
+}
+
+int ovs_ct_action_to_attr(const struct ovs_conntrack_info *ct_info,
+			  struct sk_buff *skb)
+{
+	struct nlattr *start;
+
+	start = nla_nest_start(skb, OVS_ACTION_ATTR_CT);
+	if (!start)
+		return -EMSGSIZE;
+
+	if (nla_put_u32(skb, OVS_CT_ATTR_FLAGS, ct_info->flags))
+		return -EMSGSIZE;
+	if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) &&
+	    nla_put_u16(skb, OVS_CT_ATTR_ZONE, ct_info->zone.id))
+		return -EMSGSIZE;
+
+	nla_nest_end(skb, start);
+
+	return 0;
+}
+
+void ovs_ct_free_action(const struct nlattr *a)
+{
+	struct ovs_conntrack_info *ct_info = nla_data(a);
+
+	if (ct_info->ct)
+		nf_ct_put(ct_info->ct);
+}