openvswitch: TCP flags matching support.

    tcp_flags=flags/mask
        Bitwise  match on TCP flags.  The flags and mask are 16-bit num‐
        bers written in decimal or in hexadecimal prefixed by 0x.   Each
        1-bit  in  mask requires that the corresponding bit in port must
        match.  Each 0-bit in mask causes the corresponding  bit  to  be
        ignored.

        TCP  protocol  currently  defines  9 flag bits, and additional 3
        bits are reserved (must be transmitted as zero), see  RFCs  793,
        3168, and 3540.  The flag bits are, numbering from the least
        significant bit:

        0: FIN No more data from sender.

        1: SYN Synchronize sequence numbers.

        2: RST Reset the connection.

        3: PSH Push function.

        4: ACK Acknowledgement field significant.

        5: URG Urgent pointer field significant.

        6: ECE ECN Echo.

        7: CWR Congestion Windows Reduced.

        8: NS  Nonce Sum.

        9-11:  Reserved.

        12-15: Not matchable, must be zero.
Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>

include/uapi/linux/openvswitch.h

@@ -271,6 +271,7 @@ enum ovs_key_attr {
 	OVS_KEY_ATTR_SKB_MARK,  /* u32 skb mark */
 	OVS_KEY_ATTR_TUNNEL,    /* Nested set of ovs_tunnel attributes */
 	OVS_KEY_ATTR_SCTP,      /* struct ovs_key_sctp */
+	OVS_KEY_ATTR_TCP_FLAGS,	/* be16 TCP flags. */
 
 #ifdef __KERNEL__
 	OVS_KEY_ATTR_IPV4_TUNNEL,  /* struct ovs_key_ipv4_tunnel */

net/openvswitch/flow.c

@@ -428,6 +428,7 @@ int ovs_flow_extract(struct sk_buff *skb, u16 in_port, struct sw_flow_key *key)
 				struct tcphdr *tcp = tcp_hdr(skb);
 				key->ipv4.tp.src = tcp->source;
 				key->ipv4.tp.dst = tcp->dest;
+				key->ipv4.tp.flags = TCP_FLAGS_BE16(tcp);
 			}
 		} else if (key->ip.proto == IPPROTO_UDP) {
 			if (udphdr_ok(skb)) {
@@ -496,6 +497,7 @@ int ovs_flow_extract(struct sk_buff *skb, u16 in_port, struct sw_flow_key *key)
 				struct tcphdr *tcp = tcp_hdr(skb);
 				key->ipv6.tp.src = tcp->source;
 				key->ipv6.tp.dst = tcp->dest;
+				key->ipv6.tp.flags = TCP_FLAGS_BE16(tcp);
 			}
 		} else if (key->ip.proto == NEXTHDR_UDP) {
 			if (udphdr_ok(skb)) {

net/openvswitch/flow.h

@@ -93,6 +93,7 @@ struct sw_flow_key {
 				struct {
 					__be16 src;		/* TCP/UDP/SCTP source port. */
 					__be16 dst;		/* TCP/UDP/SCTP destination port. */
+					__be16 flags;		/* TCP flags. */
 				} tp;
 				struct {
 					u8 sha[ETH_ALEN];	/* ARP source hardware address. */
@@ -109,6 +110,7 @@ struct sw_flow_key {
 			struct {
 				__be16 src;		/* TCP/UDP/SCTP source port. */
 				__be16 dst;		/* TCP/UDP/SCTP destination port. */
+				__be16 flags;		/* TCP flags. */
 			} tp;
 			struct {
 				struct in6_addr target;	/* ND target address. */

net/openvswitch/flow_netlink.c

@@ -114,6 +114,7 @@ static bool match_validate(const struct sw_flow_match *match,
 	mask_allowed &= ~((1 << OVS_KEY_ATTR_IPV4)
 			| (1 << OVS_KEY_ATTR_IPV6)
 			| (1 << OVS_KEY_ATTR_TCP)
+			| (1 << OVS_KEY_ATTR_TCP_FLAGS)
 			| (1 << OVS_KEY_ATTR_UDP)
 			| (1 << OVS_KEY_ATTR_SCTP)
 			| (1 << OVS_KEY_ATTR_ICMP)
@@ -154,8 +155,11 @@ static bool match_validate(const struct sw_flow_match *match,
 
 			if (match->key->ip.proto == IPPROTO_TCP) {
 				key_expected |= 1 << OVS_KEY_ATTR_TCP;
-				if (match->mask && (match->mask->key.ip.proto == 0xff))
+				key_expected |= 1 << OVS_KEY_ATTR_TCP_FLAGS;
+				if (match->mask && (match->mask->key.ip.proto == 0xff)) {
 					mask_allowed |= 1 << OVS_KEY_ATTR_TCP;
+					mask_allowed |= 1 << OVS_KEY_ATTR_TCP_FLAGS;
+				}
 			}
 
 			if (match->key->ip.proto == IPPROTO_ICMP) {
@@ -186,8 +190,11 @@ static bool match_validate(const struct sw_flow_match *match,
 
 			if (match->key->ip.proto == IPPROTO_TCP) {
 				key_expected |= 1 << OVS_KEY_ATTR_TCP;
-				if (match->mask && (match->mask->key.ip.proto == 0xff))
+				key_expected |= 1 << OVS_KEY_ATTR_TCP_FLAGS;
+				if (match->mask && (match->mask->key.ip.proto == 0xff)) {
 					mask_allowed |= 1 << OVS_KEY_ATTR_TCP;
+					mask_allowed |= 1 << OVS_KEY_ATTR_TCP_FLAGS;
+				}
 			}
 
 			if (match->key->ip.proto == IPPROTO_ICMPV6) {
@@ -235,6 +242,7 @@ static const int ovs_key_lens[OVS_KEY_ATTR_MAX + 1] = {
 	[OVS_KEY_ATTR_IPV4] = sizeof(struct ovs_key_ipv4),
 	[OVS_KEY_ATTR_IPV6] = sizeof(struct ovs_key_ipv6),
 	[OVS_KEY_ATTR_TCP] = sizeof(struct ovs_key_tcp),
+	[OVS_KEY_ATTR_TCP_FLAGS] = sizeof(__be16),
 	[OVS_KEY_ATTR_UDP] = sizeof(struct ovs_key_udp),
 	[OVS_KEY_ATTR_SCTP] = sizeof(struct ovs_key_sctp),
 	[OVS_KEY_ATTR_ICMP] = sizeof(struct ovs_key_icmp),
@@ -634,6 +642,19 @@ static int ovs_key_from_nlattrs(struct sw_flow_match *match,  u64 attrs,
 		attrs &= ~(1 << OVS_KEY_ATTR_TCP);
 	}
 
+	if (attrs & (1 << OVS_KEY_ATTR_TCP_FLAGS)) {
+		if (orig_attrs & (1 << OVS_KEY_ATTR_IPV4)) {
+			SW_FLOW_KEY_PUT(match, ipv4.tp.flags,
+					nla_get_be16(a[OVS_KEY_ATTR_TCP_FLAGS]),
+					is_mask);
+		} else {
+			SW_FLOW_KEY_PUT(match, ipv6.tp.flags,
+					nla_get_be16(a[OVS_KEY_ATTR_TCP_FLAGS]),
+					is_mask);
+		}
+		attrs &= ~(1 << OVS_KEY_ATTR_TCP_FLAGS);
+	}
+
 	if (attrs & (1 << OVS_KEY_ATTR_UDP)) {
 		const struct ovs_key_udp *udp_key;
 
@@ -1004,9 +1025,15 @@ int ovs_nla_put_flow(const struct sw_flow_key *swkey,
 			if (swkey->eth.type == htons(ETH_P_IP)) {
 				tcp_key->tcp_src = output->ipv4.tp.src;
 				tcp_key->tcp_dst = output->ipv4.tp.dst;
+				if (nla_put_be16(skb, OVS_KEY_ATTR_TCP_FLAGS,
+						 output->ipv4.tp.flags))
+					goto nla_put_failure;
 			} else if (swkey->eth.type == htons(ETH_P_IPV6)) {
 				tcp_key->tcp_src = output->ipv6.tp.src;
 				tcp_key->tcp_dst = output->ipv6.tp.dst;
+				if (nla_put_be16(skb, OVS_KEY_ATTR_TCP_FLAGS,
+						 output->ipv6.tp.flags))
+					goto nla_put_failure;
 			}
 		} else if (swkey->ip.proto == IPPROTO_UDP) {
 			struct ovs_key_udp *udp_key;