diff --git a/include/uapi/linux/openvswitch.h b/include/uapi/linux/openvswitch.h
index 3a6dcaa..f4bd703 100644
--- a/include/uapi/linux/openvswitch.h
+++ b/include/uapi/linux/openvswitch.h
@@ -564,6 +564,12 @@ struct ovs_action_hash {
  * @OVS_ACTION_ATTR_SET: Replaces the contents of an existing header.  The
  * single nested %OVS_KEY_ATTR_* attribute specifies a header to modify and its
  * value.
+ * @OVS_ACTION_ATTR_SET_MASKED: Replaces the contents of an existing header.  A
+ * nested %OVS_KEY_ATTR_* attribute specifies a header to modify, its value,
+ * and a mask.  For every bit set in the mask, the corresponding bit value
+ * is copied from the value to the packet header field, rest of the bits are
+ * left unchanged.  The non-masked value bits must be passed in as zeroes.
+ * Masking is not supported for the %OVS_KEY_ATTR_TUNNEL attribute.
  * @OVS_ACTION_ATTR_PUSH_VLAN: Push a new outermost 802.1Q header onto the
  * packet.
  * @OVS_ACTION_ATTR_POP_VLAN: Pop the outermost 802.1Q header off the packet.
@@ -582,6 +588,9 @@ struct ovs_action_hash {
  * Only a single header can be set with a single %OVS_ACTION_ATTR_SET.  Not all
  * fields within a header are modifiable, e.g. the IPv4 protocol and fragment
  * type may not be changed.
+ *
+ * @OVS_ACTION_ATTR_SET_TO_MASKED: Kernel internal masked set action translated
+ * from the @OVS_ACTION_ATTR_SET.
  */
 
 enum ovs_action_attr {
@@ -596,8 +605,19 @@ enum ovs_action_attr {
 	OVS_ACTION_ATTR_HASH,	      /* struct ovs_action_hash. */
 	OVS_ACTION_ATTR_PUSH_MPLS,    /* struct ovs_action_push_mpls. */
 	OVS_ACTION_ATTR_POP_MPLS,     /* __be16 ethertype. */
+	OVS_ACTION_ATTR_SET_MASKED,   /* One nested OVS_KEY_ATTR_* including
+				       * data immediately followed by a mask.
+				       * The data must be zero for the unmasked
+				       * bits. */
+
+	__OVS_ACTION_ATTR_MAX,	      /* Nothing past this will be accepted
+				       * from userspace. */
 
-	__OVS_ACTION_ATTR_MAX
+#ifdef __KERNEL__
+	OVS_ACTION_ATTR_SET_TO_MASKED, /* Kernel module internal masked
+					* set action converted from
+					* OVS_ACTION_ATTR_SET. */
+#endif
 };
 
 #define OVS_ACTION_ATTR_MAX (__OVS_ACTION_ATTR_MAX - 1)
diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index 764fdc3..ee57b9b 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -184,10 +184,15 @@ static int pop_mpls(struct sk_buff *skb, struct sw_flow_key *key,
 	return 0;
 }
 
-static int set_mpls(struct sk_buff *skb, struct sw_flow_key *key,
-		    const __be32 *mpls_lse)
+/* 'KEY' must not have any bits set outside of the 'MASK' */
+#define MASKED(OLD, KEY, MASK) ((KEY) | ((OLD) & ~(MASK)))
+#define SET_MASKED(OLD, KEY, MASK) (OLD) = MASKED(OLD, KEY, MASK)
+
+static int set_mpls(struct sk_buff *skb, struct sw_flow_key *flow_key,
+                    const __be32 *mpls_lse, const __be32 *mask)
 {
 	__be32 *stack;
+	__be32 lse;
 	int err;
 
 	err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN);
@@ -195,14 +200,15 @@ static int set_mpls(struct sk_buff *skb, struct sw_flow_key *key,
 		return err;
 
 	stack = (__be32 *)skb_mpls_header(skb);
+	lse = MASKED(*stack, *mpls_lse, *mask);
 	if (skb->ip_summed == CHECKSUM_COMPLETE) {
-		__be32 diff[] = { ~(*stack), *mpls_lse };
+		__be32 diff[] = { ~(*stack), lse };
 		skb->csum = ~csum_partial((char *)diff, sizeof(diff),
 					  ~skb->csum);
 	}
 
-	*stack = *mpls_lse;
-	key->mpls.top_lse = *mpls_lse;
+	*stack = lse;
+	flow_key->mpls.top_lse = lse;
 	return 0;
 }
 
@@ -229,8 +235,21 @@ static int push_vlan(struct sk_buff *skb, struct sw_flow_key *key,
 			     ntohs(vlan->vlan_tci) & ~VLAN_TAG_PRESENT);
 }
 
-static int set_eth_addr(struct sk_buff *skb, struct sw_flow_key *key,
-			const struct ovs_key_ethernet *eth_key)
+/* 'src' is already properly masked. */
+static void ether_addr_copy_masked(u8 *dst_, const u8 *src_, const u8 *mask_)
+{
+	u16 *dst = (u16 *)dst_;
+	const u16 *src = (const u16 *)src_;
+	const u16 *mask = (const u16 *)mask_;
+
+	SET_MASKED(dst[0], src[0], mask[0]);
+	SET_MASKED(dst[1], src[1], mask[1]);
+	SET_MASKED(dst[2], src[2], mask[2]);
+}
+
+static int set_eth_addr(struct sk_buff *skb, struct sw_flow_key *flow_key,
+			const struct ovs_key_ethernet *key,
+			const struct ovs_key_ethernet *mask)
 {
 	int err;
 	err = skb_ensure_writable(skb, ETH_HLEN);
@@ -239,13 +258,15 @@ static int set_eth_addr(struct sk_buff *skb, struct sw_flow_key *key,
 
 	skb_postpull_rcsum(skb, eth_hdr(skb), ETH_ALEN * 2);
 
-	ether_addr_copy(eth_hdr(skb)->h_source, eth_key->eth_src);
-	ether_addr_copy(eth_hdr(skb)->h_dest, eth_key->eth_dst);
+	ether_addr_copy_masked(eth_hdr(skb)->h_source, key->eth_src,
+			       mask->eth_src);
+	ether_addr_copy_masked(eth_hdr(skb)->h_dest, key->eth_dst,
+			       mask->eth_dst);
 
 	ovs_skb_postpush_rcsum(skb, eth_hdr(skb), ETH_ALEN * 2);
 
-	ether_addr_copy(key->eth.src, eth_key->eth_src);
-	ether_addr_copy(key->eth.dst, eth_key->eth_dst);
+	ether_addr_copy(flow_key->eth.src, eth_hdr(skb)->h_source);
+	ether_addr_copy(flow_key->eth.dst, eth_hdr(skb)->h_dest);
 	return 0;
 }
 
@@ -303,6 +324,15 @@ static void update_ipv6_checksum(struct sk_buff *skb, u8 l4_proto,
 	}
 }
 
+static void mask_ipv6_addr(const __be32 old[4], const __be32 addr[4],
+			   const __be32 mask[4], __be32 masked[4])
+{
+	masked[0] = MASKED(old[0], addr[0], mask[0]);
+	masked[1] = MASKED(old[1], addr[1], mask[1]);
+	masked[2] = MASKED(old[2], addr[2], mask[2]);
+	masked[3] = MASKED(old[3], addr[3], mask[3]);
+}
+
 static void set_ipv6_addr(struct sk_buff *skb, u8 l4_proto,
 			  __be32 addr[4], const __be32 new_addr[4],
 			  bool recalculate_csum)
@@ -314,29 +344,29 @@ static void set_ipv6_addr(struct sk_buff *skb, u8 l4_proto,
 	memcpy(addr, new_addr, sizeof(__be32[4]));
 }
 
-static void set_ipv6_tc(struct ipv6hdr *nh, u8 tc)
+static void set_ipv6_fl(struct ipv6hdr *nh, u32 fl, u32 mask)
 {
-	nh->priority = tc >> 4;
-	nh->flow_lbl[0] = (nh->flow_lbl[0] & 0x0F) | ((tc & 0x0F) << 4);
+	/* Bits 21-24 are always unmasked, so this retains their values. */
+	SET_MASKED(nh->flow_lbl[0], (u8)(fl >> 16), (u8)(mask >> 16));
+	SET_MASKED(nh->flow_lbl[1], (u8)(fl >> 8), (u8)(mask >> 8));
+	SET_MASKED(nh->flow_lbl[2], (u8)fl, (u8)mask);
 }
 
-static void set_ipv6_fl(struct ipv6hdr *nh, u32 fl)
+static void set_ip_ttl(struct sk_buff *skb, struct iphdr *nh, u8 new_ttl,
+		       u8 mask)
 {
-	nh->flow_lbl[0] = (nh->flow_lbl[0] & 0xF0) | (fl & 0x000F0000) >> 16;
-	nh->flow_lbl[1] = (fl & 0x0000FF00) >> 8;
-	nh->flow_lbl[2] = fl & 0x000000FF;
-}
+	new_ttl = MASKED(nh->ttl, new_ttl, mask);
 
-static void set_ip_ttl(struct sk_buff *skb, struct iphdr *nh, u8 new_ttl)
-{
 	csum_replace2(&nh->check, htons(nh->ttl << 8), htons(new_ttl << 8));
 	nh->ttl = new_ttl;
 }
 
-static int set_ipv4(struct sk_buff *skb, struct sw_flow_key *key,
-		    const struct ovs_key_ipv4 *ipv4_key)
+static int set_ipv4(struct sk_buff *skb, struct sw_flow_key *flow_key,
+		    const struct ovs_key_ipv4 *key,
+		    const struct ovs_key_ipv4 *mask)
 {
 	struct iphdr *nh;
+	__be32 new_addr;
 	int err;
 
 	err = skb_ensure_writable(skb, skb_network_offset(skb) +
@@ -346,36 +376,48 @@ static int set_ipv4(struct sk_buff *skb, struct sw_flow_key *key,
 
 	nh = ip_hdr(skb);
 
-	if (ipv4_key->ipv4_src != nh->saddr) {
-		set_ip_addr(skb, nh, &nh->saddr, ipv4_key->ipv4_src);
-		key->ipv4.addr.src = ipv4_key->ipv4_src;
-	}
+	/* Setting an IP addresses is typically only a side effect of
+	 * matching on them in the current userspace implementation, so it
+	 * makes sense to check if the value actually changed. */
+	if (mask->ipv4_src) {
+		new_addr = MASKED(nh->saddr, key->ipv4_src, mask->ipv4_src);
 
-	if (ipv4_key->ipv4_dst != nh->daddr) {
-		set_ip_addr(skb, nh, &nh->daddr, ipv4_key->ipv4_dst);
-		key->ipv4.addr.dst = ipv4_key->ipv4_dst;
+		if (unlikely(new_addr != nh->saddr)) {
+			set_ip_addr(skb, nh, &nh->saddr, new_addr);
+			flow_key->ipv4.addr.src = new_addr;
+		}
 	}
+	if (mask->ipv4_dst) {
+		new_addr = MASKED(nh->daddr, key->ipv4_dst, mask->ipv4_dst);
 
-	if (ipv4_key->ipv4_tos != nh->tos) {
-		ipv4_change_dsfield(nh, 0, ipv4_key->ipv4_tos);
-		key->ip.tos = nh->tos;
+		if (unlikely(new_addr != nh->daddr)) {
+			set_ip_addr(skb, nh, &nh->daddr, new_addr);
+			flow_key->ipv4.addr.dst = new_addr;
+		}
 	}
-
-	if (ipv4_key->ipv4_ttl != nh->ttl) {
-		set_ip_ttl(skb, nh, ipv4_key->ipv4_ttl);
-		key->ip.ttl = ipv4_key->ipv4_ttl;
+	if (mask->ipv4_tos) {
+		ipv4_change_dsfield(nh, ~mask->ipv4_tos, key->ipv4_tos);
+		flow_key->ip.tos = nh->tos;
+	}
+	if (mask->ipv4_ttl) {
+		set_ip_ttl(skb, nh, key->ipv4_ttl, mask->ipv4_ttl);
+		flow_key->ip.ttl = nh->ttl;
 	}
 
 	return 0;
 }
 
-static int set_ipv6(struct sk_buff *skb, struct sw_flow_key *key,
-		    const struct ovs_key_ipv6 *ipv6_key)
+static bool is_ipv6_mask_nonzero(const __be32 addr[4])
+{
+	return !!(addr[0] | addr[1] | addr[2] | addr[3]);
+}
+
+static int set_ipv6(struct sk_buff *skb, struct sw_flow_key *flow_key,
+		    const struct ovs_key_ipv6 *key,
+		    const struct ovs_key_ipv6 *mask)
 {
 	struct ipv6hdr *nh;
 	int err;
-	__be32 *saddr;
-	__be32 *daddr;
 
 	err = skb_ensure_writable(skb, skb_network_offset(skb) +
 				  sizeof(struct ipv6hdr));
@@ -383,40 +425,59 @@ static int set_ipv6(struct sk_buff *skb, struct sw_flow_key *key,
 		return err;
 
 	nh = ipv6_hdr(skb);
-	saddr = (__be32 *)&nh->saddr;
-	daddr = (__be32 *)&nh->daddr;
-
-	if (memcmp(ipv6_key->ipv6_src, saddr, sizeof(ipv6_key->ipv6_src))) {
-		set_ipv6_addr(skb, ipv6_key->ipv6_proto, saddr,
-			      ipv6_key->ipv6_src, true);
-		memcpy(&key->ipv6.addr.src, ipv6_key->ipv6_src,
-		       sizeof(ipv6_key->ipv6_src));
-	}
 
-	if (memcmp(ipv6_key->ipv6_dst, daddr, sizeof(ipv6_key->ipv6_dst))) {
+	/* Setting an IP addresses is typically only a side effect of
+	 * matching on them in the current userspace implementation, so it
+	 * makes sense to check if the value actually changed. */
+	if (is_ipv6_mask_nonzero(mask->ipv6_src)) {
+		__be32 *saddr = (__be32 *)&nh->saddr;
+		__be32 masked[4];
+
+		mask_ipv6_addr(saddr, key->ipv6_src, mask->ipv6_src, masked);
+
+		if (unlikely(memcmp(saddr, masked, sizeof masked))) {
+			set_ipv6_addr(skb, key->ipv6_proto, saddr, masked,
+				      true);
+			memcpy(&flow_key->ipv6.addr.src, masked,
+			       sizeof(flow_key->ipv6.addr.src));
+		}
+	}
+	if (is_ipv6_mask_nonzero(mask->ipv6_dst)) {
 		unsigned int offset = 0;
 		int flags = IP6_FH_F_SKIP_RH;
 		bool recalc_csum = true;
-
-		if (ipv6_ext_hdr(nh->nexthdr))
-			recalc_csum = ipv6_find_hdr(skb, &offset,
-						    NEXTHDR_ROUTING, NULL,
-						    &flags) != NEXTHDR_ROUTING;
-
-		set_ipv6_addr(skb, ipv6_key->ipv6_proto, daddr,
-			      ipv6_key->ipv6_dst, recalc_csum);
-		memcpy(&key->ipv6.addr.dst, ipv6_key->ipv6_dst,
-		       sizeof(ipv6_key->ipv6_dst));
+		__be32 *daddr = (__be32 *)&nh->daddr;
+		__be32 masked[4];
+
+		mask_ipv6_addr(daddr, key->ipv6_dst, mask->ipv6_dst, masked);
+
+		if (unlikely(memcmp(daddr, masked, sizeof masked))) {
+			if (ipv6_ext_hdr(nh->nexthdr))
+				recalc_csum = (ipv6_find_hdr(skb, &offset,
+							     NEXTHDR_ROUTING,
+							     NULL, &flags)
+					       != NEXTHDR_ROUTING);
+
+			set_ipv6_addr(skb, key->ipv6_proto, daddr, masked,
+				      recalc_csum);
+			memcpy(&flow_key->ipv6.addr.dst, masked,
+			       sizeof(flow_key->ipv6.addr.dst));
+		}
+	}
+	if (mask->ipv6_tclass) {
+		ipv6_change_dsfield(nh, ~mask->ipv6_tclass, key->ipv6_tclass);
+		flow_key->ip.tos = ipv6_get_dsfield(nh);
+	}
+	if (mask->ipv6_label) {
+		set_ipv6_fl(nh, ntohl(key->ipv6_label),
+			    ntohl(mask->ipv6_label));
+		flow_key->ipv6.label =
+		    *(__be32 *)nh & htonl(IPV6_FLOWINFO_FLOWLABEL);
+	}
+	if (mask->ipv6_hlimit) {
+		SET_MASKED(nh->hop_limit, key->ipv6_hlimit, mask->ipv6_hlimit);
+		flow_key->ip.ttl = nh->hop_limit;
 	}
-
-	set_ipv6_tc(nh, ipv6_key->ipv6_tclass);
-	key->ip.tos = ipv6_get_dsfield(nh);
-
-	set_ipv6_fl(nh, ntohl(ipv6_key->ipv6_label));
-	key->ipv6.label = *(__be32 *)nh & htonl(IPV6_FLOWINFO_FLOWLABEL);
-
-	nh->hop_limit = ipv6_key->ipv6_hlimit;
-	key->ip.ttl = ipv6_key->ipv6_hlimit;
 	return 0;
 }
 
@@ -426,28 +487,14 @@ static void set_tp_port(struct sk_buff *skb, __be16 *port,
 {
 	inet_proto_csum_replace2(check, skb, *port, new_port, 0);
 	*port = new_port;
-	skb_clear_hash(skb);
-}
-
-static void set_udp_port(struct sk_buff *skb, __be16 *port, __be16 new_port)
-{
-	struct udphdr *uh = udp_hdr(skb);
-
-	if (uh->check && skb->ip_summed != CHECKSUM_PARTIAL) {
-		set_tp_port(skb, port, new_port, &uh->check);
-
-		if (!uh->check)
-			uh->check = CSUM_MANGLED_0;
-	} else {
-		*port = new_port;
-		skb_clear_hash(skb);
-	}
 }
 
-static int set_udp(struct sk_buff *skb, struct sw_flow_key *key,
-		   const struct ovs_key_udp *udp_port_key)
+static int set_udp(struct sk_buff *skb, struct sw_flow_key *flow_key,
+		   const struct ovs_key_udp *key,
+		   const struct ovs_key_udp *mask)
 {
 	struct udphdr *uh;
+	__be16 src, dst;
 	int err;
 
 	err = skb_ensure_writable(skb, skb_transport_offset(skb) +
@@ -456,23 +503,40 @@ static int set_udp(struct sk_buff *skb, struct sw_flow_key *key,
 		return err;
 
 	uh = udp_hdr(skb);
-	if (udp_port_key->udp_src != uh->source) {
-		set_udp_port(skb, &uh->source, udp_port_key->udp_src);
-		key->tp.src = udp_port_key->udp_src;
-	}
+        /* Either of the masks is non-zero, so do not bother checking them. */
+	src = MASKED(uh->source, key->udp_src, mask->udp_src);
+	dst = MASKED(uh->dest, key->udp_dst, mask->udp_dst);
 
-	if (udp_port_key->udp_dst != uh->dest) {
-		set_udp_port(skb, &uh->dest, udp_port_key->udp_dst);
-		key->tp.dst = udp_port_key->udp_dst;
+	if (uh->check && skb->ip_summed != CHECKSUM_PARTIAL) {
+		if (likely(src != uh->source)) {
+			set_tp_port(skb, &uh->source, src, &uh->check);
+			flow_key->tp.src = src;
+		}
+		if (likely(dst != uh->dest)) {
+			set_tp_port(skb, &uh->dest, dst, &uh->check);
+			flow_key->tp.dst = dst;
+		}
+
+		if (unlikely(!uh->check))
+			uh->check = CSUM_MANGLED_0;
+	} else {
+		uh->source = src;
+		uh->dest = dst;
+		flow_key->tp.src = src;
+		flow_key->tp.dst = dst;
 	}
 
+	skb_clear_hash(skb);
+
 	return 0;
 }
 
-static int set_tcp(struct sk_buff *skb, struct sw_flow_key *key,
-		   const struct ovs_key_tcp *tcp_port_key)
+static int set_tcp(struct sk_buff *skb, struct sw_flow_key *flow_key,
+		   const struct ovs_key_tcp *key,
+		   const struct ovs_key_tcp *mask)
 {
 	struct tcphdr *th;
+	__be16 src, dst;
 	int err;
 
 	err = skb_ensure_writable(skb, skb_transport_offset(skb) +
@@ -481,50 +545,49 @@ static int set_tcp(struct sk_buff *skb, struct sw_flow_key *key,
 		return err;
 
 	th = tcp_hdr(skb);
-	if (tcp_port_key->tcp_src != th->source) {
-		set_tp_port(skb, &th->source, tcp_port_key->tcp_src, &th->check);
-		key->tp.src = tcp_port_key->tcp_src;
+	src = MASKED(th->source, key->tcp_src, mask->tcp_src);
+	if (likely(src != th->source)) {
+		set_tp_port(skb, &th->source, src, &th->check);
+		flow_key->tp.src = src;
 	}
-
-	if (tcp_port_key->tcp_dst != th->dest) {
-		set_tp_port(skb, &th->dest, tcp_port_key->tcp_dst, &th->check);
-		key->tp.dst = tcp_port_key->tcp_dst;
+	dst = MASKED(th->dest, key->tcp_dst, mask->tcp_dst);
+	if (likely(dst != th->dest)) {
+		set_tp_port(skb, &th->dest, dst, &th->check);
+		flow_key->tp.dst = dst;
 	}
+	skb_clear_hash(skb);
 
 	return 0;
 }
 
-static int set_sctp(struct sk_buff *skb, struct sw_flow_key *key,
-		    const struct ovs_key_sctp *sctp_port_key)
+static int set_sctp(struct sk_buff *skb, struct sw_flow_key *flow_key,
+		    const struct ovs_key_sctp *key,
+		    const struct ovs_key_sctp *mask)
 {
+	unsigned int sctphoff = skb_transport_offset(skb);
 	struct sctphdr *sh;
+	__le32 old_correct_csum, new_csum, old_csum;
 	int err;
-	unsigned int sctphoff = skb_transport_offset(skb);
 
 	err = skb_ensure_writable(skb, sctphoff + sizeof(struct sctphdr));
 	if (unlikely(err))
 		return err;
 
 	sh = sctp_hdr(skb);
-	if (sctp_port_key->sctp_src != sh->source ||
-	    sctp_port_key->sctp_dst != sh->dest) {
-		__le32 old_correct_csum, new_csum, old_csum;
-
-		old_csum = sh->checksum;
-		old_correct_csum = sctp_compute_cksum(skb, sctphoff);
+	old_csum = sh->checksum;
+	old_correct_csum = sctp_compute_cksum(skb, sctphoff);
 
-		sh->source = sctp_port_key->sctp_src;
-		sh->dest = sctp_port_key->sctp_dst;
+	sh->source = MASKED(sh->source, key->sctp_src, mask->sctp_src);
+	sh->dest = MASKED(sh->dest, key->sctp_dst, mask->sctp_dst);
 
-		new_csum = sctp_compute_cksum(skb, sctphoff);
+	new_csum = sctp_compute_cksum(skb, sctphoff);
 
-		/* Carry any checksum errors through. */
-		sh->checksum = old_csum ^ old_correct_csum ^ new_csum;
+	/* Carry any checksum errors through. */
+	sh->checksum = old_csum ^ old_correct_csum ^ new_csum;
 
-		skb_clear_hash(skb);
-		key->tp.src = sctp_port_key->sctp_src;
-		key->tp.dst = sctp_port_key->sctp_dst;
-	}
+	skb_clear_hash(skb);
+	flow_key->tp.src = sh->source;
+	flow_key->tp.dst = sh->dest;
 
 	return 0;
 }
@@ -652,52 +715,77 @@ static void execute_hash(struct sk_buff *skb, struct sw_flow_key *key,
 	key->ovs_flow_hash = hash;
 }
 
-static int execute_set_action(struct sk_buff *skb, struct sw_flow_key *key,
-			      const struct nlattr *nested_attr)
+static int execute_set_action(struct sk_buff *skb,
+			      struct sw_flow_key *flow_key,
+			      const struct nlattr *a)
+{
+	/* Only tunnel set execution is supported without a mask. */
+	if (nla_type(a) == OVS_KEY_ATTR_TUNNEL_INFO) {
+		OVS_CB(skb)->egress_tun_info = nla_data(a);
+		return 0;
+	}
+
+	return -EINVAL;
+
+}
+
+/* Mask is at the midpoint of the data. */
+#define get_mask(a, type) ((const type *)nla_data(a) + 1)
+
+static int execute_masked_set_action(struct sk_buff *skb,
+				     struct sw_flow_key *flow_key,
+				     const struct nlattr *a)
 {
 	int err = 0;
 
-	switch (nla_type(nested_attr)) {
+	switch (nla_type(a)) {
 	case OVS_KEY_ATTR_PRIORITY:
-		skb->priority = nla_get_u32(nested_attr);
-		key->phy.priority = skb->priority;
+		SET_MASKED(skb->priority, nla_get_u32(a), *get_mask(a, u32));
+		flow_key->phy.priority = skb->priority;
 		break;
 
 	case OVS_KEY_ATTR_SKB_MARK:
-		skb->mark = nla_get_u32(nested_attr);
-		key->phy.skb_mark = skb->mark;
+		SET_MASKED(skb->mark, nla_get_u32(a), *get_mask(a, u32));
+		flow_key->phy.skb_mark = skb->mark;
 		break;
 
 	case OVS_KEY_ATTR_TUNNEL_INFO:
-		OVS_CB(skb)->egress_tun_info = nla_data(nested_attr);
+		/* Masked data not supported for tunnel. */
+		err = -EINVAL;
 		break;
 
 	case OVS_KEY_ATTR_ETHERNET:
-		err = set_eth_addr(skb, key, nla_data(nested_attr));
+		err = set_eth_addr(skb, flow_key, nla_data(a),
+				   get_mask(a, struct ovs_key_ethernet));
 		break;
 
 	case OVS_KEY_ATTR_IPV4:
-		err = set_ipv4(skb, key, nla_data(nested_attr));
+		err = set_ipv4(skb, flow_key, nla_data(a),
+			       get_mask(a, struct ovs_key_ipv4));
 		break;
 
 	case OVS_KEY_ATTR_IPV6:
-		err = set_ipv6(skb, key, nla_data(nested_attr));
+		err = set_ipv6(skb, flow_key, nla_data(a),
+			       get_mask(a, struct ovs_key_ipv6));
 		break;
 
 	case OVS_KEY_ATTR_TCP:
-		err = set_tcp(skb, key, nla_data(nested_attr));
+		err = set_tcp(skb, flow_key, nla_data(a),
+			      get_mask(a, struct ovs_key_tcp));
 		break;
 
 	case OVS_KEY_ATTR_UDP:
-		err = set_udp(skb, key, nla_data(nested_attr));
+		err = set_udp(skb, flow_key, nla_data(a),
+			      get_mask(a, struct ovs_key_udp));
 		break;
 
 	case OVS_KEY_ATTR_SCTP:
-		err = set_sctp(skb, key, nla_data(nested_attr));
+		err = set_sctp(skb, flow_key, nla_data(a),
+			       get_mask(a, struct ovs_key_sctp));
 		break;
 
 	case OVS_KEY_ATTR_MPLS:
-		err = set_mpls(skb, key, nla_data(nested_attr));
+		err = set_mpls(skb, flow_key, nla_data(a), get_mask(a, __be32));
 		break;
 	}
 
@@ -817,6 +905,11 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
 			err = execute_set_action(skb, key, nla_data(a));
 			break;
 
+		case OVS_ACTION_ATTR_SET_MASKED:
+		case OVS_ACTION_ATTR_SET_TO_MASKED:
+			err = execute_masked_set_action(skb, key, nla_data(a));
+			break;
+
 		case OVS_ACTION_ATTR_SAMPLE:
 			err = sample(dp, skb, key, a);
 			break;
diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
index df3c7f2..276bb60 100644
--- a/net/openvswitch/flow_netlink.c
+++ b/net/openvswitch/flow_netlink.c
@@ -1609,23 +1609,44 @@ static int validate_and_copy_set_tun(const struct nlattr *attr,
 	return err;
 }
 
+/* Return false if there are any non-masked bits set.
+ * Mask follows data immediately, before any netlink padding. */
+static bool validate_masked(u8 *data, int len)
+{
+	u8 *mask = data + len;
+
+	while (len--)
+		if (*data++ & ~*mask++)
+			return false;
+
+	return true;
+}
+
 static int validate_set(const struct nlattr *a,
 			const struct sw_flow_key *flow_key,
 			struct sw_flow_actions **sfa,
-			bool *set_tun, __be16 eth_type, bool log)
+			bool *skip_copy, __be16 eth_type, bool masked, bool log)
 {
 	const struct nlattr *ovs_key = nla_data(a);
 	int key_type = nla_type(ovs_key);
+	size_t key_len;
 
 	/* There can be only one key in a action */
 	if (nla_total_size(nla_len(ovs_key)) != nla_len(a))
 		return -EINVAL;
 
+	key_len = nla_len(ovs_key);
+	if (masked)
+		key_len /= 2;
+
 	if (key_type > OVS_KEY_ATTR_MAX ||
-	    (ovs_key_lens[key_type] != nla_len(ovs_key) &&
+	    (ovs_key_lens[key_type] != key_len &&
 	     ovs_key_lens[key_type] != -1))
 		return -EINVAL;
 
+	if (masked && !validate_masked(nla_data(ovs_key), key_len))
+		return -EINVAL;
+
 	switch (key_type) {
 	const struct ovs_key_ipv4 *ipv4_key;
 	const struct ovs_key_ipv6 *ipv6_key;
@@ -1640,7 +1661,10 @@ static int validate_set(const struct nlattr *a,
 		if (eth_p_mpls(eth_type))
 			return -EINVAL;
 
-		*set_tun = true;
+		if (masked)
+			return -EINVAL; /* Masked tunnel set not supported. */
+
+		*skip_copy = true;
 		err = validate_and_copy_set_tun(a, sfa, log);
 		if (err)
 			return err;
@@ -1650,32 +1674,46 @@ static int validate_set(const struct nlattr *a,
 		if (eth_type != htons(ETH_P_IP))
 			return -EINVAL;
 
-		if (!flow_key->ip.proto)
-			return -EINVAL;
-
 		ipv4_key = nla_data(ovs_key);
-		if (ipv4_key->ipv4_proto != flow_key->ip.proto)
-			return -EINVAL;
 
-		if (ipv4_key->ipv4_frag != flow_key->ip.frag)
-			return -EINVAL;
+		if (masked) {
+			const struct ovs_key_ipv4 *mask = ipv4_key + 1;
 
+			/* Non-writeable fields. */
+			if (mask->ipv4_proto || mask->ipv4_frag)
+				return -EINVAL;
+		} else {
+			if (ipv4_key->ipv4_proto != flow_key->ip.proto)
+				return -EINVAL;
+
+			if (ipv4_key->ipv4_frag != flow_key->ip.frag)
+				return -EINVAL;
+		}
 		break;
 
 	case OVS_KEY_ATTR_IPV6:
 		if (eth_type != htons(ETH_P_IPV6))
 			return -EINVAL;
 
-		if (!flow_key->ip.proto)
-			return -EINVAL;
-
 		ipv6_key = nla_data(ovs_key);
-		if (ipv6_key->ipv6_proto != flow_key->ip.proto)
-			return -EINVAL;
 
-		if (ipv6_key->ipv6_frag != flow_key->ip.frag)
-			return -EINVAL;
+		if (masked) {
+			const struct ovs_key_ipv6 *mask = ipv6_key + 1;
 
+			/* Non-writeable fields. */
+			if (mask->ipv6_proto || mask->ipv6_frag)
+				return -EINVAL;
+
+			/* Invalid bits in the flow label mask? */
+			if (ntohl(mask->ipv6_label) & 0xFFF00000)
+				return -EINVAL;
+		} else {
+			if (ipv6_key->ipv6_proto != flow_key->ip.proto)
+				return -EINVAL;
+
+			if (ipv6_key->ipv6_frag != flow_key->ip.frag)
+				return -EINVAL;
+		}
 		if (ntohl(ipv6_key->ipv6_label) & 0xFFF00000)
 			return -EINVAL;
 
@@ -1685,13 +1723,19 @@ static int validate_set(const struct nlattr *a,
 		if (flow_key->ip.proto != IPPROTO_TCP)
 			return -EINVAL;
 
-		return validate_tp_port(flow_key, eth_type);
+		err = validate_tp_port(flow_key, eth_type);
+		if (err)
+			return err;
+		break;
 
 	case OVS_KEY_ATTR_UDP:
 		if (flow_key->ip.proto != IPPROTO_UDP)
 			return -EINVAL;
 
-		return validate_tp_port(flow_key, eth_type);
+		err = validate_tp_port(flow_key, eth_type);
+		if (err)
+			return err;
+		break;
 
 	case OVS_KEY_ATTR_MPLS:
 		if (!eth_p_mpls(eth_type))
@@ -1702,12 +1746,43 @@ static int validate_set(const struct nlattr *a,
 		if (flow_key->ip.proto != IPPROTO_SCTP)
 			return -EINVAL;
 
-		return validate_tp_port(flow_key, eth_type);
+		err = validate_tp_port(flow_key, eth_type);
+		if (err)
+			return err;
+		break;
 
 	default:
 		return -EINVAL;
 	}
 
+	/* Convert non-masked non-tunnel set actions to masked set actions. */
+	if (!masked && key_type != OVS_KEY_ATTR_TUNNEL) {
+		int start, len = key_len * 2;
+		struct nlattr *at;
+
+		*skip_copy = true;
+
+		start = add_nested_action_start(sfa,
+						OVS_ACTION_ATTR_SET_TO_MASKED,
+						log);
+		if (start < 0)
+			return start;
+
+		at = __add_action(sfa, key_type, NULL, len, log);
+		if (IS_ERR(at))
+			return PTR_ERR(at);
+
+		memcpy(nla_data(at), nla_data(ovs_key), key_len); /* Key. */
+		memset(nla_data(at) + key_len, 0xff, key_len);    /* Mask. */
+		/* Clear non-writeable bits from otherwise writeable fields. */
+		if (key_type == OVS_KEY_ATTR_IPV6) {
+			struct ovs_key_ipv6 *mask = nla_data(at) + key_len;
+
+			mask->ipv6_label &= htonl(0x000FFFFF);
+		}
+		add_nested_action_end(*sfa, start);
+	}
+
 	return 0;
 }
 
@@ -1770,6 +1845,7 @@ static int __ovs_nla_copy_actions(const struct nlattr *attr,
 			[OVS_ACTION_ATTR_PUSH_VLAN] = sizeof(struct ovs_action_push_vlan),
 			[OVS_ACTION_ATTR_POP_VLAN] = 0,
 			[OVS_ACTION_ATTR_SET] = (u32)-1,
+			[OVS_ACTION_ATTR_SET_MASKED] = (u32)-1,
 			[OVS_ACTION_ATTR_SAMPLE] = (u32)-1,
 			[OVS_ACTION_ATTR_HASH] = sizeof(struct ovs_action_hash)
 		};
@@ -1872,12 +1948,20 @@ static int __ovs_nla_copy_actions(const struct nlattr *attr,
 			break;
 
 		case OVS_ACTION_ATTR_SET:
-			err = validate_set(a, key, sfa,
-					   &out_tnl_port, eth_type, log);
+			err = validate_set(a, key, sfa, &skip_copy, eth_type,
+					   false, log);
 			if (err)
 				return err;
 
-			skip_copy = out_tnl_port;
+			if (nla_type(nla_data(a)) == OVS_KEY_ATTR_TUNNEL)
+				out_tnl_port = true;
+			break;
+
+		case OVS_ACTION_ATTR_SET_MASKED:
+			err = validate_set(a, key, sfa, &skip_copy, eth_type,
+					   true, log);
+			if (err)
+				return err;
 			break;
 
 		case OVS_ACTION_ATTR_SAMPLE:
@@ -1905,6 +1989,7 @@ static int __ovs_nla_copy_actions(const struct nlattr *attr,
 	return 0;
 }
 
+/* 'key' must be the masked key. */
 int ovs_nla_copy_actions(const struct nlattr *attr,
 			 const struct sw_flow_key *key,
 			 struct sw_flow_actions **sfa, bool log)
@@ -1992,6 +2077,31 @@ static int set_action_to_attr(const struct nlattr *a, struct sk_buff *skb)
 	return 0;
 }
 
+static int masked_set_action_to_attr(const struct nlattr *a,
+				     struct sk_buff *skb)
+{
+	const struct nlattr *ovs_key = nla_data(a);
+
+	if (nla_put(skb, OVS_ACTION_ATTR_SET_MASKED, nla_len(a), ovs_key))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
+static int masked_set_action_to_set_action_attr(const struct nlattr *a,
+						struct sk_buff *skb)
+{
+	const struct nlattr *ovs_key = nla_data(a);
+	size_t key_len = nla_len(ovs_key) / 2;
+
+	/* Revert the conversion we did from a non-masked set action to
+	 * masked set action. */
+	if (nla_put(skb, OVS_ACTION_ATTR_SET, nla_len(a) - key_len, ovs_key))
+		return -EMSGSIZE;
+
+	return 0;
+}
+
 int ovs_nla_put_actions(const struct nlattr *attr, int len, struct sk_buff *skb)
 {
 	const struct nlattr *a;
@@ -2007,6 +2117,18 @@ int ovs_nla_put_actions(const struct nlattr *attr, int len, struct sk_buff *skb)
 				return err;
 			break;
 
+		case OVS_ACTION_ATTR_SET_MASKED:
+			err = masked_set_action_to_attr(a, skb);
+			if (err)
+				return err;
+			break;
+
+		case OVS_ACTION_ATTR_SET_TO_MASKED:
+			err = masked_set_action_to_set_action_attr(a, skb);
+			if (err)
+				return err;
+			break;
+
 		case OVS_ACTION_ATTR_SAMPLE:
 			err = sample_action_to_attr(a, skb);
 			if (err)
