diff --git a/acinclude.m4 b/acinclude.m4
index 911a23d..04da8a4 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -254,6 +254,13 @@ AC_DEFUN([OVS_CHECK_LINUX_COMPAT], [
   OVS_GREP_IFELSE([$KSRC/include/linux/skbuff.h], [consume_skb])
   OVS_GREP_IFELSE([$KSRC/include/linux/skbuff.h], [skb_frag_page])
   OVS_GREP_IFELSE([$KSRC/include/linux/skbuff.h], [skb_reset_mac_len])
+  # If encapsulation_features is merged upstream then a release number may
+  # be used to select compatibility code and the following check may be
+  # removed. This check is here for now to allow Open vSwtich to provide
+  # an example of how encapsulation_features may be used to provide
+  # GSO of non-MPLS GSO skbs that are turned into MPLS GSO skbs
+  # using MPLS push actions
+  OVS_GREP_IFELSE([$KSRC/include/linux/skbuff.h], [encapsulation_features])
 
   OVS_GREP_IFELSE([$KSRC/include/linux/string.h], [kmemdup], [],
                   [OVS_GREP_IFELSE([$KSRC/include/linux/slab.h], [kmemdup])])
diff --git a/datapath/actions.c b/datapath/actions.c
index 0dac658..6e96931 100644
--- a/datapath/actions.c
+++ b/datapath/actions.c
@@ -38,6 +38,7 @@
 #include "vport.h"
 
 static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
+			      unsigned *mpls_stack_depth,
 			      const struct nlattr *attr, int len, bool keep_skb);
 
 static int make_writable(struct sk_buff *skb, int write_len)
@@ -48,6 +49,100 @@ static int make_writable(struct sk_buff *skb, int write_len)
 	return pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
 }
 
+static void set_ethertype(struct sk_buff *skb, const __be16 ethertype)
+{
+	/* skb_mac_header hdr is not used to locate the ethertype to
+	 * set as it will be incorrect in the presence of VLAN tags
+	 */
+	struct ethhdr *hdr = (struct ethhdr *)(skb_network_header(skb) -
+					       ETH_HLEN);
+	if (hdr->h_proto == ethertype)
+		return;
+	hdr->h_proto = ethertype;
+	if (get_ip_summed(skb) == OVS_CSUM_COMPLETE) {
+		__be16 diff[] = { ~hdr->h_proto, ethertype };
+		skb->csum = ~csum_partial((char *)diff, sizeof(diff),
+					  ~skb->csum);
+	}
+}
+
+static int push_mpls(struct sk_buff *skb,
+		     const struct ovs_action_push_mpls *mpls,
+		     unsigned *mpls_stack_depth)
+{
+	__be32 *new_mpls_lse;
+	int err;
+
+	err = make_writable(skb, skb->mac_len + MPLS_HLEN);
+	if (unlikely(err))
+		return err;
+
+	skb_push(skb, MPLS_HLEN);
+	memmove(skb_mac_header(skb) - MPLS_HLEN, skb_mac_header(skb),
+		skb->mac_len);
+	skb_reset_mac_header(skb);
+	skb_set_network_header(skb, skb->mac_len);
+
+	new_mpls_lse = (__be32 *)skb_network_header(skb);
+	*new_mpls_lse = mpls->mpls_lse;
+
+	if (get_ip_summed(skb) == OVS_CSUM_COMPLETE)
+		skb->csum = csum_add(skb->csum, csum_partial(new_mpls_lse,
+							     MPLS_HLEN, 0));
+
+	set_ethertype(skb, mpls->mpls_ethertype);
+	if (!eth_p_mpls(skb->protocol))
+		(*mpls_stack_depth)++;
+	return 0;
+}
+
+static int pop_mpls(struct sk_buff *skb, const __be16 *ethertype,
+		    unsigned *mpls_stack_depth)
+{
+	int err;
+
+	err = make_writable(skb, skb->mac_len + MPLS_HLEN);
+	if (unlikely(err))
+		return err;
+
+	if (get_ip_summed(skb) == OVS_CSUM_COMPLETE)
+		skb->csum = csum_sub(skb->csum,
+				     csum_partial(skb_network_header(skb),
+						  MPLS_HLEN, 0));
+
+	memmove(skb_mac_header(skb) + MPLS_HLEN, skb_mac_header(skb),
+		skb->mac_len);
+
+	skb_pull(skb, MPLS_HLEN);
+	skb_reset_mac_header(skb);
+	skb_set_network_header(skb, skb->mac_len);
+
+	set_ethertype(skb, *ethertype);
+	if (!eth_p_mpls(skb->protocol))
+		(*mpls_stack_depth)--;
+	return 0;
+}
+
+static int set_mpls(struct sk_buff *skb, const __be32 *mpls_lse)
+{
+	__be32 *stack = (__be32 *)skb_network_header(skb);
+	int err;
+
+	err = make_writable(skb, skb->mac_len + MPLS_HLEN);
+	if (unlikely(err))
+		return err;
+
+	if (get_ip_summed(skb) == OVS_CSUM_COMPLETE) {
+		__be32 diff[] = { ~(*stack), *mpls_lse };
+		skb->csum = ~csum_partial((char *)diff, sizeof(diff),
+					  ~skb->csum);
+	}
+
+	*stack = *mpls_lse;
+
+	return 0;
+}
+
 /* remove VLAN header from packet and update csum accordingly. */
 static int __pop_vlan_tci(struct sk_buff *skb, __be16 *current_tci)
 {
@@ -115,6 +210,9 @@ static int push_vlan(struct sk_buff *skb, const struct ovs_action_push_vlan *vla
 		if (!__vlan_put_tag(skb, current_tag))
 			return -ENOMEM;
 
+		/* update mac_len for MPLS functions */
+		skb_reset_mac_len(skb);
+
 		if (get_ip_summed(skb) == OVS_CSUM_COMPLETE)
 			skb->csum = csum_add(skb->csum, csum_partial(skb->data
 					+ (2 * ETH_ALEN), VLAN_HLEN, 0));
@@ -352,13 +450,31 @@ static int set_tcp(struct sk_buff *skb, const struct ovs_key_tcp *tcp_port_key)
 	return 0;
 }
 
-static int do_output(struct datapath *dp, struct sk_buff *skb, int out_port)
+static int do_output(struct datapath *dp, struct sk_buff *skb, int out_port,
+		     unsigned mpls_stack_depth)
 {
 	struct vport *vport;
 
 	if (unlikely(!skb))
 		return -ENOMEM;
 
+	/* During action execution the network_header, and mac_len,
+	 * correspondingly, have tracked the end of the L2 frame (including
+	 * any VLAN headers), but proper skb output processing of GSO skbs
+	 * requires the network_header (and mac_len) to track the start of
+	 * the L3 header instead. These differ in the presence of MPLS
+	 * headers.
+	 *
+	 * mpls_stack_depth is only non-zero if a non-MPLS skb is turned
+	 * into an MPLS skb via an MPLS push action. This is the only case
+	 * where an MPLS skb may be a GSO skb.
+	 */
+	if (mpls_stack_depth) {
+		skb->mac_len += MPLS_HLEN * mpls_stack_depth;
+		skb_set_network_header(skb, skb->mac_len);
+		skb_set_encapsulation_features(skb);
+	}
+
 	vport = ovs_vport_rcu(dp, out_port);
 	if (unlikely(!vport)) {
 		kfree_skb(skb);
@@ -398,7 +514,7 @@ static int output_userspace(struct datapath *dp, struct sk_buff *skb,
 }
 
 static int sample(struct datapath *dp, struct sk_buff *skb,
-		  const struct nlattr *attr)
+		  unsigned *mpls_stack_depth, const struct nlattr *attr)
 {
 	const struct nlattr *acts_list = NULL;
 	const struct nlattr *a;
@@ -418,8 +534,9 @@ static int sample(struct datapath *dp, struct sk_buff *skb,
 		}
 	}
 
-	return do_execute_actions(dp, skb, nla_data(acts_list),
-				  nla_len(acts_list), true);
+	return do_execute_actions(dp, skb, mpls_stack_depth,
+				  nla_data(acts_list), nla_len(acts_list),
+				  true);
 }
 
 static int execute_set_action(struct sk_buff *skb,
@@ -459,13 +576,23 @@ static int execute_set_action(struct sk_buff *skb,
 	case OVS_KEY_ATTR_UDP:
 		err = set_udp(skb, nla_data(nested_attr));
 		break;
+
+	case OVS_KEY_ATTR_MPLS:
+		err = set_mpls(skb, nla_data(nested_attr));
+		break;
 	}
 
 	return err;
 }
 
-/* Execute a list of actions against 'skb'. */
+/* Execute a list of actions against 'skb'.
+ *
+ * The stack depth is only tracked in the case of a non-MPLS packet
+ * that becomes MPLS via an MPLS push action. The stack depth
+ * is passed to do_output() in order to allow it to prepare the
+ * skb for possible GSO segmentation. */
 static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
+			unsigned *mpls_stack_depth,
 			const struct nlattr *attr, int len, bool keep_skb)
 {
 	/* Every output action needs a separate clone of 'skb', but the common
@@ -481,7 +608,8 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
 		int err = 0;
 
 		if (prev_port != -1) {
-			do_output(dp, skb_clone(skb, GFP_ATOMIC), prev_port);
+			do_output(dp, skb_clone(skb, GFP_ATOMIC),
+				  prev_port, *mpls_stack_depth);
 			prev_port = -1;
 		}
 
@@ -494,6 +622,14 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
 			output_userspace(dp, skb, a);
 			break;
 
+		case OVS_ACTION_ATTR_PUSH_MPLS:
+			err = push_mpls(skb, nla_data(a), mpls_stack_depth);
+			break;
+
+		case OVS_ACTION_ATTR_POP_MPLS:
+			err = pop_mpls(skb, nla_data(a), mpls_stack_depth);
+			break;
+
 		case OVS_ACTION_ATTR_PUSH_VLAN:
 			err = push_vlan(skb, nla_data(a));
 			if (unlikely(err)) /* skb already freed. */
@@ -509,7 +645,7 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
 			break;
 
 		case OVS_ACTION_ATTR_SAMPLE:
-			err = sample(dp, skb, a);
+			err = sample(dp, skb, mpls_stack_depth, a);
 			break;
 		}
 
@@ -523,7 +659,7 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
 		if (keep_skb)
 			skb = skb_clone(skb, GFP_ATOMIC);
 
-		do_output(dp, skb, prev_port);
+		do_output(dp, skb, prev_port, *mpls_stack_depth);
 	} else if (!keep_skb)
 		consume_skb(skb);
 
@@ -556,6 +692,7 @@ int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb)
 	struct sw_flow_actions *acts = rcu_dereference(OVS_CB(skb)->flow->sf_acts);
 	struct loop_counter *loop;
 	int error;
+	unsigned mpls_stack_depth = 0;
 
 	/* Check whether we've looped too much. */
 	loop = &__get_cpu_var(loop_counters);
@@ -568,7 +705,7 @@ int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb)
 	}
 
 	OVS_CB(skb)->tun_key = NULL;
-	error = do_execute_actions(dp, skb, acts->actions,
+	error = do_execute_actions(dp, skb, &mpls_stack_depth, acts->actions,
 					 acts->actions_len, false);
 
 	/* Check whether sub-actions looped too much. */
diff --git a/datapath/datapath.c b/datapath/datapath.c
index 3cb58b0..e4ed5e0 100644
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -550,13 +550,26 @@ static inline void add_nested_action_end(struct sw_flow_actions *sfa, int st_off
 	a->nla_len = sfa->actions_len - st_offset;
 }
 
-static int validate_and_copy_actions(const struct nlattr *attr,
+struct eth_types {
+	size_t depth;
+	__be16 types[SAMPLE_ACTION_DEPTH];
+};
+
+static void eth_types_set(struct eth_types *types, size_t depth, __be16 type)
+{
+	types->depth = depth;
+	types->types[depth] = type;
+}
+
+static int validate_and_copy_actions__(const struct nlattr *attr,
 				const struct sw_flow_key *key, int depth,
-				struct sw_flow_actions **sfa);
+				struct sw_flow_actions **sfa,
+				struct eth_types *eth_types);
 
 static int validate_and_copy_sample(const struct nlattr *attr,
 			   const struct sw_flow_key *key, int depth,
-			   struct sw_flow_actions **sfa)
+			   struct sw_flow_actions **sfa,
+			   struct eth_types *eth_types)
 {
 	const struct nlattr *attrs[OVS_SAMPLE_ATTR_MAX + 1];
 	const struct nlattr *probability, *actions;
@@ -592,7 +605,8 @@ static int validate_and_copy_sample(const struct nlattr *attr,
 	if (st_acts < 0)
 		return st_acts;
 
-	err = validate_and_copy_actions(actions, key, depth + 1, sfa);
+	err = validate_and_copy_actions__(actions, key, depth + 1, sfa,
+					  eth_types);
 	if (err)
 		return err;
 
@@ -602,12 +616,12 @@ static int validate_and_copy_sample(const struct nlattr *attr,
 	return 0;
 }
 
-static int validate_tp_port(const struct sw_flow_key *flow_key)
+static int validate_tp_port(const struct sw_flow_key *flow_key, __be16 eth_type)
 {
-	if (flow_key->eth.type == htons(ETH_P_IP)) {
+	if (eth_type == htons(ETH_P_IP)) {
 		if (flow_key->ipv4.tp.src || flow_key->ipv4.tp.dst)
 			return 0;
-	} else if (flow_key->eth.type == htons(ETH_P_IPV6)) {
+	} else 	if (eth_type == htons(ETH_P_IPV6)) {
 		if (flow_key->ipv6.tp.src || flow_key->ipv6.tp.dst)
 			return 0;
 	}
@@ -638,7 +652,7 @@ static int validate_and_copy_set_tun(const struct nlattr *attr,
 static int validate_set(const struct nlattr *a,
 			const struct sw_flow_key *flow_key,
 			struct sw_flow_actions **sfa,
-			bool *set_tun)
+			bool *set_tun, struct eth_types *eth_types)
 {
 	const struct nlattr *ovs_key = nla_data(a);
 	int key_type = nla_type(ovs_key);
@@ -675,9 +689,12 @@ static int validate_set(const struct nlattr *a,
 			return err;
 		break;
 
-	case OVS_KEY_ATTR_IPV4:
-		if (flow_key->eth.type != htons(ETH_P_IP))
-			return -EINVAL;
+	case OVS_KEY_ATTR_IPV4: {
+		size_t i;
+
+		for (i = 0; i < eth_types->depth; i++)
+			if (eth_types->types[i] != htons(ETH_P_IP))
+				return -EINVAL;
 
 		if (!flow_key->ip.proto)
 			return -EINVAL;
@@ -690,10 +707,14 @@ static int validate_set(const struct nlattr *a,
 			return -EINVAL;
 
 		break;
+	}
 
-	case OVS_KEY_ATTR_IPV6:
-		if (flow_key->eth.type != htons(ETH_P_IPV6))
-			return -EINVAL;
+	case OVS_KEY_ATTR_IPV6: {
+		size_t i;
+
+		for (i = 0; i < eth_types->depth; i++)
+			if (eth_types->types[i] != htons(ETH_P_IPV6))
+				return -EINVAL;
 
 		if (!flow_key->ip.proto)
 			return -EINVAL;
@@ -709,18 +730,37 @@ static int validate_set(const struct nlattr *a,
 			return -EINVAL;
 
 		break;
+	}
+
+	case OVS_KEY_ATTR_TCP: {
+		size_t i;
 
-	case OVS_KEY_ATTR_TCP:
 		if (flow_key->ip.proto != IPPROTO_TCP)
 			return -EINVAL;
 
-		return validate_tp_port(flow_key);
+		for (i = 0; i < eth_types->depth; i++)
+			if (validate_tp_port(flow_key, eth_types->types[i]))
+				return -EINVAL;
+	}
 
-	case OVS_KEY_ATTR_UDP:
+	case OVS_KEY_ATTR_UDP: {
+		size_t i;
 		if (flow_key->ip.proto != IPPROTO_UDP)
 			return -EINVAL;
 
-		return validate_tp_port(flow_key);
+		for (i = 0; i < eth_types->depth; i++)
+			if (validate_tp_port(flow_key, eth_types->types[i]))
+				return -EINVAL;
+	}
+
+	case OVS_KEY_ATTR_MPLS: {
+		size_t i;
+
+		for (i = 0; i < eth_types->depth; i++)
+			if (!eth_p_mpls(eth_types->types[i]))
+				return -EINVAL;
+		break;
+	}
 
 	default:
 		return -EINVAL;
@@ -764,10 +804,10 @@ static int copy_action(const struct nlattr *from,
 	return 0;
 }
 
-static int validate_and_copy_actions(const struct nlattr *attr,
-				const struct sw_flow_key *key,
-				int depth,
-				struct sw_flow_actions **sfa)
+static int validate_and_copy_actions__(const struct nlattr *attr,
+				const struct sw_flow_key *key, int depth,
+				struct sw_flow_actions **sfa,
+				struct eth_types *eth_types)
 {
 	const struct nlattr *a;
 	int rem, err;
@@ -775,11 +815,29 @@ static int validate_and_copy_actions(const struct nlattr *attr,
 	if (depth >= SAMPLE_ACTION_DEPTH)
 		return -EOVERFLOW;
 
+	/* Due to the sample action there may be more than one possibility
+	 * for the current ethernet type. They all need to be verified.
+	 *
+	 * This is handled by tracking a stack of ethernet types, one for
+	 * each (sample) depth of validation. Here the ethernet type for
+	 * the current depth is pushed onto the stack. It may be modified
+	 * as by actions are validated. When a modification occurs the
+	 * ethernet types for higher stack-depths are popped off the stack.
+	 * All entries on the stack are checked when validating the
+	 * ethernet type required by an action.
+	 */
+	if (!depth)
+		eth_types_set(eth_types, 0, key->eth.type);
+	else
+		eth_types_set(eth_types, depth, eth_types->types[depth - 1]);
+
 	nla_for_each_nested(a, attr, rem) {
 		/* Expected argument lengths, (u32)-1 for variable length. */
 		static const u32 action_lens[OVS_ACTION_ATTR_MAX + 1] = {
 			[OVS_ACTION_ATTR_OUTPUT] = sizeof(u32),
 			[OVS_ACTION_ATTR_USERSPACE] = (u32)-1,
+			[OVS_ACTION_ATTR_PUSH_MPLS] = sizeof(struct ovs_action_push_mpls),
+			[OVS_ACTION_ATTR_POP_MPLS] = sizeof(__be16),
 			[OVS_ACTION_ATTR_PUSH_VLAN] = sizeof(struct ovs_action_push_vlan),
 			[OVS_ACTION_ATTR_POP_VLAN] = 0,
 			[OVS_ACTION_ATTR_SET] = (u32)-1,
@@ -810,6 +868,35 @@ static int validate_and_copy_actions(const struct nlattr *attr,
 				return -EINVAL;
 			break;
 
+		case OVS_ACTION_ATTR_PUSH_MPLS: {
+			const struct ovs_action_push_mpls *mpls = nla_data(a);
+			if (!eth_p_mpls(mpls->mpls_ethertype))
+				return -EINVAL;
+			eth_types_set(eth_types, depth, mpls->mpls_ethertype);
+			break;
+		}
+
+		case OVS_ACTION_ATTR_POP_MPLS: {
+			size_t i;
+
+			for (i = 0; i < eth_types->depth; i++)
+				if (eth_types->types[i] != htons(ETH_P_IP))
+					return -EINVAL;
+
+			/* Disallow subsequent l2.5+ set and mpls_pop actions
+			 * as there is no check here to ensure that the new
+			 * eth_type is valid and thus set actions could
+			 * write off the end of the packet or otherwise
+			 * corrupt it.
+			 *
+			 * Support for these actions that after mpls_pop
+			 * using packet recirculation is planned.
+			 * are planned to be supported using using packet
+			 * recirculation.
+			 */
+			eth_types_set(eth_types, depth, htons(0));
+			break;
+		}
 
 		case OVS_ACTION_ATTR_POP_VLAN:
 			break;
@@ -823,13 +910,14 @@ static int validate_and_copy_actions(const struct nlattr *attr,
 			break;
 
 		case OVS_ACTION_ATTR_SET:
-			err = validate_set(a, key, sfa, &skip_copy);
+			err = validate_set(a, key, sfa, &skip_copy, eth_types);
 			if (err)
 				return err;
 			break;
 
 		case OVS_ACTION_ATTR_SAMPLE:
-			err = validate_and_copy_sample(a, key, depth, sfa);
+			err = validate_and_copy_sample(a, key, depth, sfa,
+						       eth_types);
 			if (err)
 				return err;
 			skip_copy = true;
@@ -851,6 +939,14 @@ static int validate_and_copy_actions(const struct nlattr *attr,
 	return 0;
 }
 
+static int validate_and_copy_actions(const struct nlattr *attr,
+				const struct sw_flow_key *key,
+				struct sw_flow_actions **sfa)
+{
+	struct eth_types eth_type;
+	return validate_and_copy_actions__(attr, key, 0, sfa, &eth_type);
+}
+
 static void clear_stats(struct sw_flow *flow)
 {
 	flow->used = 0;
@@ -915,7 +1011,7 @@ static int ovs_packet_cmd_execute(struct sk_buff *skb, struct genl_info *info)
 	if (IS_ERR(acts))
 		goto err_flow_free;
 
-	err = validate_and_copy_actions(a[OVS_PACKET_ATTR_ACTIONS], &flow->key, 0, &acts);
+	err = validate_and_copy_actions(a[OVS_PACKET_ATTR_ACTIONS], &flow->key, &acts);
 	rcu_assign_pointer(flow->sf_acts, acts);
 	if (err)
 		goto err_flow_free;
@@ -1251,7 +1347,7 @@ static int ovs_flow_cmd_new_or_set(struct sk_buff *skb, struct genl_info *info)
 		if (IS_ERR(acts))
 			goto error;
 
-		error = validate_and_copy_actions(a[OVS_FLOW_ATTR_ACTIONS], &key,  0, &acts);
+		error = validate_and_copy_actions(a[OVS_FLOW_ATTR_ACTIONS], &key,  &acts);
 		if (error)
 			goto err_kfree;
 	} else if (info->genlhdr->cmd == OVS_FLOW_CMD_NEW) {
diff --git a/datapath/datapath.h b/datapath/datapath.h
index ad59a3a..4f0f4e1 100644
--- a/datapath/datapath.h
+++ b/datapath/datapath.h
@@ -202,4 +202,6 @@ struct sk_buff *ovs_vport_cmd_build_info(struct vport *, u32 portid, u32 seq,
 
 int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb);
 void ovs_dp_notify_wq(struct work_struct *work);
+
+unsigned char *skb_cb_mpls_stack(const struct sk_buff *skb);
 #endif /* datapath.h */
diff --git a/datapath/flow.c b/datapath/flow.c
index 3ce926e..a9d6434 100644
--- a/datapath/flow.c
+++ b/datapath/flow.c
@@ -648,6 +648,7 @@ int ovs_flow_extract(struct sk_buff *skb, u16 in_port, struct sw_flow_key *key,
 		return -ENOMEM;
 
 	skb_reset_network_header(skb);
+	skb_reset_mac_len(skb);
 	__skb_push(skb, skb->data - skb_mac_header(skb));
 
 	/* Network layer. */
@@ -730,6 +731,13 @@ int ovs_flow_extract(struct sk_buff *skb, u16 in_port, struct sw_flow_key *key,
 			memcpy(key->ipv4.arp.tha, arp->ar_tha, ETH_ALEN);
 			key_len = SW_FLOW_KEY_OFFSET(ipv4.arp);
 		}
+	} else if (eth_p_mpls(key->eth.type)) {
+		error = check_header(skb, MPLS_HLEN);
+		if (unlikely(error))
+			goto out;
+
+		key_len = SW_FLOW_KEY_OFFSET(mpls.top_lse);
+		memcpy(&key->mpls.top_lse, skb_network_header(skb), MPLS_HLEN);
 	} else if (key->eth.type == htons(ETH_P_IPV6)) {
 		int nh_len;             /* IPv6 Header + Extensions */
 
@@ -848,6 +856,9 @@ const int ovs_key_lens[OVS_KEY_ATTR_MAX + 1] = {
 	[OVS_KEY_ATTR_ARP] = sizeof(struct ovs_key_arp),
 	[OVS_KEY_ATTR_ND] = sizeof(struct ovs_key_nd),
 	[OVS_KEY_ATTR_TUNNEL] = -1,
+
+	/* Not upstream. */
+	[OVS_KEY_ATTR_MPLS] = sizeof(struct ovs_key_mpls),
 };
 
 static int ipv4_flow_from_nlattrs(struct sw_flow_key *swkey, int *key_len,
@@ -1254,6 +1265,15 @@ int ovs_flow_from_nlattrs(struct sw_flow_key *swkey, int *key_lenp,
 		swkey->ip.proto = ntohs(arp_key->arp_op);
 		memcpy(swkey->ipv4.arp.sha, arp_key->arp_sha, ETH_ALEN);
 		memcpy(swkey->ipv4.arp.tha, arp_key->arp_tha, ETH_ALEN);
+	} else if (eth_p_mpls(swkey->eth.type)) {
+		const struct ovs_key_mpls *mpls_key;
+		if (!(attrs & (1ULL << OVS_KEY_ATTR_MPLS)))
+			return -EINVAL;
+		attrs &= ~(1ULL << OVS_KEY_ATTR_MPLS);
+
+		key_len = SW_FLOW_KEY_OFFSET(mpls.top_lse);
+		mpls_key = nla_data(a[OVS_KEY_ATTR_MPLS]);
+		swkey->mpls.top_lse = mpls_key->mpls_lse;
 	}
 
 	if (attrs)
@@ -1420,6 +1440,14 @@ int ovs_flow_to_nlattrs(const struct sw_flow_key *swkey, struct sk_buff *skb)
 		arp_key->arp_op = htons(swkey->ip.proto);
 		memcpy(arp_key->arp_sha, swkey->ipv4.arp.sha, ETH_ALEN);
 		memcpy(arp_key->arp_tha, swkey->ipv4.arp.tha, ETH_ALEN);
+	} else if (eth_p_mpls(swkey->eth.type)) {
+		struct ovs_key_mpls *mpls_key;
+
+		nla = nla_reserve(skb, OVS_KEY_ATTR_MPLS, sizeof(*mpls_key));
+		if (!nla)
+			goto nla_put_failure;
+		mpls_key = nla_data(nla);
+		mpls_key->mpls_lse = swkey->mpls.top_lse;
 	}
 
 	if ((swkey->eth.type == htons(ETH_P_IP) ||
diff --git a/datapath/flow.h b/datapath/flow.h
index dba66cf..2e3083b 100644
--- a/datapath/flow.h
+++ b/datapath/flow.h
@@ -72,12 +72,17 @@ struct sw_flow_key {
 		__be16 tci;		/* 0 if no VLAN, VLAN_TAG_PRESENT set otherwise. */
 		__be16 type;		/* Ethernet frame type. */
 	} eth;
-	struct {
-		u8     proto;		/* IP protocol or lower 8 bits of ARP opcode. */
-		u8     tos;		/* IP ToS. */
-		u8     ttl;		/* IP TTL/hop limit. */
-		u8     frag;		/* One of OVS_FRAG_TYPE_*. */
-	} ip;
+	union {
+		struct {
+			__be32 top_lse;		/* top label stack entry */
+		} mpls;
+		struct {
+			u8     proto;		/* IP protocol or lower 8 bits of ARP opcode. */
+			u8     tos;		/* IP ToS. */
+			u8     ttl;		/* IP TTL/hop limit. */
+			u8     frag;		/* One of OVS_FRAG_TYPE_*. */
+		} ip;
+	};
 	union {
 		struct {
 			struct {
@@ -143,6 +148,8 @@ struct arp_eth_header {
 	unsigned char       ar_tip[4];		/* target IP address        */
 } __packed;
 
+#define MPLS_HLEN 4
+
 int ovs_flow_init(void);
 void ovs_flow_exit(void);
 
@@ -204,4 +211,10 @@ int ipv4_tun_from_nlattr(const struct nlattr *attr,
 int ipv4_tun_to_nlattr(struct sk_buff *skb,
 			const struct ovs_key_ipv4_tunnel *tun_key);
 
+static inline bool eth_p_mpls(__be16 eth_type)
+{
+	return eth_type == htons(ETH_P_MPLS_UC) ||
+		eth_type == htons(ETH_P_MPLS_MC);
+}
+
 #endif /* flow.h */
diff --git a/datapath/linux/compat/include/linux/skbuff.h b/datapath/linux/compat/include/linux/skbuff.h
index d485b39..f620a0a 100644
--- a/datapath/linux/compat/include/linux/skbuff.h
+++ b/datapath/linux/compat/include/linux/skbuff.h
@@ -251,4 +251,14 @@ static inline void skb_reset_mac_len(struct sk_buff *skb)
 	skb->mac_len = skb->network_header - skb->mac_header;
 }
 #endif
+
+#ifdef HAVE_ENCAPSULATION_FEATURES
+static inline void skb_set_encapsulation_features(struct sk_buff *skb)
+{
+	skb->encapsulation_features = 1;
+}
+#else
+/* MPLS GSO is not supported */
+static inline void skb_set_encapsulation_features(struct sk_buff *skb) { }
+#endif
 #endif
diff --git a/include/linux/openvswitch.h b/include/linux/openvswitch.h
index bd2f05f..e890fd8 100644
--- a/include/linux/openvswitch.h
+++ b/include/linux/openvswitch.h
@@ -287,7 +287,9 @@ enum ovs_key_attr {
 	OVS_KEY_ATTR_IPV4_TUNNEL,  /* struct ovs_key_ipv4_tunnel */
 #endif
 
-	OVS_KEY_ATTR_MPLS = 62, /* struct ovs_key_mpls */
+	OVS_KEY_ATTR_MPLS = 62, /* array of struct ovs_key_mpls.
+				 * The implementation may restrict
+				 * the accepted length of the array. */
 	__OVS_KEY_ATTR_MAX
 };
 
@@ -330,7 +332,7 @@ struct ovs_key_ethernet {
 };
 
 struct ovs_key_mpls {
-	__be32 mpls_top_lse;
+	__be32 mpls_lse;
 };
 
 struct ovs_key_ipv4 {
diff --git a/lib/odp-util.c b/lib/odp-util.c
index 751c1c9..3206dc9 100644
--- a/lib/odp-util.c
+++ b/lib/odp-util.c
@@ -906,7 +906,7 @@ format_odp_key_attr(const struct nlattr *a, struct ds *ds)
     case OVS_KEY_ATTR_MPLS: {
         const struct ovs_key_mpls *mpls_key = nl_attr_get(a);
         ds_put_char(ds, '(');
-        format_mpls_lse(ds, mpls_key->mpls_top_lse);
+        format_mpls_lse(ds, mpls_key->mpls_lse);
         ds_put_char(ds, ')');
         break;
     }
@@ -1231,7 +1231,7 @@ parse_odp_key_attr(const char *s, const struct simap *port_names,
 
             mpls = nl_msg_put_unspec_uninit(key, OVS_KEY_ATTR_MPLS,
                                             sizeof *mpls);
-            mpls->mpls_top_lse = mpls_lse_from_components(label, tc, ttl, bos);
+            mpls->mpls_lse = mpls_lse_from_components(label, tc, ttl, bos);
             return n;
         }
     }
@@ -1594,7 +1594,7 @@ odp_flow_key_from_flow(struct ofpbuf *buf, const struct flow *flow,
 
         mpls_key = nl_msg_put_unspec_uninit(buf, OVS_KEY_ATTR_MPLS,
                                             sizeof *mpls_key);
-        mpls_key->mpls_top_lse = flow->mpls_lse;
+        mpls_key->mpls_lse = flow->mpls_lse;
     }
 
     if (is_ip_any(flow) && !(flow->nw_frag & FLOW_NW_FRAG_LATER)) {
@@ -2250,7 +2250,7 @@ commit_mpls_action(const struct flow *flow, struct flow *base,
     } else {
         struct ovs_key_mpls mpls_key;
 
-        mpls_key.mpls_top_lse = flow->mpls_lse;
+        mpls_key.mpls_lse = flow->mpls_lse;
         commit_set_action(odp_actions, OVS_KEY_ATTR_MPLS,
                           &mpls_key, sizeof(mpls_key));
     }
