nfp: flower: implement tcp flag match offload

Implement tcp flag match offloading. Current tcp flag match support include
FIN, SYN, RST, PSH and URG flags, other flags are unsupported. The PSH and
URG flags are only set in the hardware fast path when used in combination
with the SYN, RST and PSH flags.
Signed-off-by: NPieter Jansen van Vuuren <pieter.jansenvanvuuren@netronome.com>
Reviewed-by: NJohn Hurley <john.hurley@netronome.com>
Reviewed-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/flower/cmsg.h

@@ -61,6 +61,13 @@
 #define NFP_FLOWER_MASK_MPLS_BOS	BIT(8)
 #define NFP_FLOWER_MASK_MPLS_Q		BIT(0)
 
+/* Compressed HW representation of TCP Flags */
+#define NFP_FL_TCP_FLAG_URG		BIT(4)
+#define NFP_FL_TCP_FLAG_PSH		BIT(3)
+#define NFP_FL_TCP_FLAG_RST		BIT(2)
+#define NFP_FL_TCP_FLAG_SYN		BIT(1)
+#define NFP_FL_TCP_FLAG_FIN		BIT(0)
+
 #define NFP_FL_SC_ACT_DROP		0x80000000
 #define NFP_FL_SC_ACT_USER		0x7D000000
 #define NFP_FL_SC_ACT_POPV		0x6A000000
@@ -257,7 +264,7 @@ struct nfp_flower_tp_ports {
  *    3                   2                   1
  *  1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
- * |    DSCP   |ECN|   protocol    |           reserved            |
+ * |    DSCP   |ECN|   protocol    |      ttl      |     flags     |
  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  * |                        ipv4_addr_src                          |
  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
@@ -268,7 +275,7 @@ struct nfp_flower_ipv4 {
 	u8 tos;
 	u8 proto;
 	u8 ttl;
-	u8 reserved;
+	u8 flags;
 	__be32 ipv4_src;
 	__be32 ipv4_dst;
 };

drivers/net/ethernet/netronome/nfp/flower/main.h

@@ -41,6 +41,7 @@
 #include <linux/time64.h>
 #include <linux/types.h>
 #include <net/pkt_cls.h>
+#include <net/tcp.h>
 #include <linux/workqueue.h>
 
 struct net_device;

drivers/net/ethernet/netronome/nfp/flower/match.c

@@ -181,6 +181,26 @@ nfp_flower_compile_ipv4(struct nfp_flower_ipv4 *frame,
 		frame->tos = flow_ip->tos;
 		frame->ttl = flow_ip->ttl;
 	}
+
+	if (dissector_uses_key(flow->dissector, FLOW_DISSECTOR_KEY_TCP)) {
+		struct flow_dissector_key_tcp *tcp;
+		u32 tcp_flags;
+
+		tcp = skb_flow_dissector_target(flow->dissector,
+						FLOW_DISSECTOR_KEY_TCP, target);
+		tcp_flags = be16_to_cpu(tcp->flags);
+
+		if (tcp_flags & TCPHDR_FIN)
+			frame->flags |= NFP_FL_TCP_FLAG_FIN;
+		if (tcp_flags & TCPHDR_SYN)
+			frame->flags |= NFP_FL_TCP_FLAG_SYN;
+		if (tcp_flags & TCPHDR_RST)
+			frame->flags |= NFP_FL_TCP_FLAG_RST;
+		if (tcp_flags & TCPHDR_PSH)
+			frame->flags |= NFP_FL_TCP_FLAG_PSH;
+		if (tcp_flags & TCPHDR_URG)
+			frame->flags |= NFP_FL_TCP_FLAG_URG;
+	}
 }
 
 static void

drivers/net/ethernet/netronome/nfp/flower/offload.c

@@ -44,11 +44,16 @@
 #include "../nfp_net.h"
 #include "../nfp_port.h"
 
+#define NFP_FLOWER_SUPPORTED_TCPFLAGS \
+	(TCPHDR_FIN | TCPHDR_SYN | TCPHDR_RST | \
+	 TCPHDR_PSH | TCPHDR_URG)
+
 #define NFP_FLOWER_WHITELIST_DISSECTOR \
 	(BIT(FLOW_DISSECTOR_KEY_CONTROL) | \
 	 BIT(FLOW_DISSECTOR_KEY_BASIC) | \
 	 BIT(FLOW_DISSECTOR_KEY_IPV4_ADDRS) | \
 	 BIT(FLOW_DISSECTOR_KEY_IPV6_ADDRS) | \
+	 BIT(FLOW_DISSECTOR_KEY_TCP) | \
 	 BIT(FLOW_DISSECTOR_KEY_PORTS) | \
 	 BIT(FLOW_DISSECTOR_KEY_ETH_ADDRS) | \
 	 BIT(FLOW_DISSECTOR_KEY_VLAN) | \
@@ -288,6 +293,35 @@ nfp_flower_calculate_key_layers(struct nfp_app *app,
 		}
 	}
 
+	if (dissector_uses_key(flow->dissector, FLOW_DISSECTOR_KEY_TCP)) {
+		struct flow_dissector_key_tcp *tcp;
+		u32 tcp_flags;
+
+		tcp = skb_flow_dissector_target(flow->dissector,
+						FLOW_DISSECTOR_KEY_TCP,
+						flow->key);
+		tcp_flags = be16_to_cpu(tcp->flags);
+
+		if (tcp_flags & ~NFP_FLOWER_SUPPORTED_TCPFLAGS)
+			return -EOPNOTSUPP;
+
+		/* We only support PSH and URG flags when either
+		 * FIN, SYN or RST is present as well.
+		 */
+		if ((tcp_flags & (TCPHDR_PSH | TCPHDR_URG)) &&
+		    !(tcp_flags & (TCPHDR_FIN | TCPHDR_SYN | TCPHDR_RST)))
+			return -EOPNOTSUPP;
+
+		/* We need to store TCP flags in the IPv4 key space, thus
+		 * we need to ensure we include a IPv4 key layer if we have
+		 * not done so already.
+		 */
+		if (!(key_layer & NFP_FLOWER_LAYER_IPV4)) {
+			key_layer |= NFP_FLOWER_LAYER_IPV4;
+			key_size += sizeof(struct nfp_flower_ipv4);
+		}
+	}
+
 	ret_key_ls->key_layer = key_layer;
 	ret_key_ls->key_layer_two = key_layer_two;
 	ret_key_ls->key_size = key_size;