nfp: flower: add GRE decap classification support

Extend the existing tunnel matching support to include GRE decap
classification. Specifically matching existing tunnel fields for
NVGRE (GRE with protocol field set to TEB).
Signed-off-by: Pieter Jansen van Vuuren <pieter.jansenvanvuuren@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -8,6 +8,7 @@
 #include <linux/skbuff.h>
 #include <linux/types.h>
 #include <net/geneve.h>
+#include <net/gre.h>
 #include <net/vxlan.h>
 
 #include "../nfp_app.h"
@@ -22,6 +23,7 @@
 #define NFP_FLOWER_LAYER_CT		BIT(6)
 #define NFP_FLOWER_LAYER_VXLAN		BIT(7)
 
+#define NFP_FLOWER_LAYER2_GRE		BIT(0)
 #define NFP_FLOWER_LAYER2_GENEVE	BIT(5)
 #define NFP_FLOWER_LAYER2_GENEVE_OP	BIT(6)
 
@@ -37,6 +39,9 @@
 #define NFP_FL_IP_FRAG_FIRST		BIT(7)
 #define NFP_FL_IP_FRAGMENTED		BIT(6)
 
+/* GRE Tunnel flags */
+#define NFP_FL_GRE_FLAG_KEY		BIT(2)
+
 /* Compressed HW representation of TCP Flags */
 #define NFP_FL_TCP_FLAG_URG		BIT(4)
 #define NFP_FL_TCP_FLAG_PSH		BIT(3)
@@ -107,6 +112,7 @@
 
 enum nfp_flower_tun_type {
 	NFP_FL_TUNNEL_NONE =	0,
+	NFP_FL_TUNNEL_GRE =	1,
 	NFP_FL_TUNNEL_VXLAN =	2,
 	NFP_FL_TUNNEL_GENEVE =	4,
 };
@@ -388,6 +394,35 @@ struct nfp_flower_ipv4_udp_tun {
 	__be32 tun_id;
 };
 
+/* Flow Frame GRE TUNNEL --> Tunnel details (6W/24B)
+ * -----------------------------------------------------------------
+ *    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
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                         ipv4_addr_src                         |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                         ipv4_addr_dst                         |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |           tun_flags           |       tos     |       ttl     |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |            Reserved           |           Ethertype           |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                              Key                              |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                           Reserved                            |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+
+struct nfp_flower_ipv4_gre_tun {
+	struct nfp_flower_tun_ipv4 ipv4;
+	__be16 tun_flags;
+	struct nfp_flower_tun_ip_ext ip_ext;
+	__be16 reserved1;
+	__be16 ethertype;
+	__be32 tun_key;
+	__be32 reserved2;
+};
+
 struct nfp_flower_geneve_options {
 	u8 data[NFP_FL_MAX_GENEVE_OPT_KEY];
 };
@@ -538,6 +573,8 @@ nfp_fl_netdev_is_tunnel_type(struct net_device *netdev,
 {
 	if (netif_is_vxlan(netdev))
 		return tun_type == NFP_FL_TUNNEL_VXLAN;
+	if (netif_is_gretap(netdev))
+		return tun_type == NFP_FL_TUNNEL_GRE;
 	if (netif_is_geneve(netdev))
 		return tun_type == NFP_FL_TUNNEL_GENEVE;
 
@@ -554,6 +591,8 @@ static inline bool nfp_fl_is_netdev_to_offload(struct net_device *netdev)
 		return true;
 	if (netif_is_geneve(netdev))
 		return true;
+	if (netif_is_gretap(netdev))
+		return true;
 
 	return false;
 }

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

@@ -316,6 +316,35 @@ nfp_flower_compile_tun_ip_ext(struct nfp_flower_tun_ip_ext *ext,
 	}
 }
 
+static void
+nfp_flower_compile_ipv4_gre_tun(struct nfp_flower_ipv4_gre_tun *ext,
+				struct nfp_flower_ipv4_gre_tun *msk,
+				struct tc_cls_flower_offload *flow)
+{
+	struct flow_rule *rule = tc_cls_flower_offload_flow_rule(flow);
+
+	memset(ext, 0, sizeof(struct nfp_flower_ipv4_gre_tun));
+	memset(msk, 0, sizeof(struct nfp_flower_ipv4_gre_tun));
+
+	/* NVGRE is the only supported GRE tunnel type */
+	ext->ethertype = cpu_to_be16(ETH_P_TEB);
+	msk->ethertype = cpu_to_be16(~0);
+
+	if (flow_rule_match_key(rule, FLOW_DISSECTOR_KEY_ENC_KEYID)) {
+		struct flow_match_enc_keyid match;
+
+		flow_rule_match_enc_keyid(rule, &match);
+		ext->tun_key = match.key->keyid;
+		msk->tun_key = match.mask->keyid;
+
+		ext->tun_flags = cpu_to_be16(NFP_FL_GRE_FLAG_KEY);
+		msk->tun_flags = cpu_to_be16(NFP_FL_GRE_FLAG_KEY);
+	}
+
+	nfp_flower_compile_tun_ipv4_addrs(&ext->ipv4, &msk->ipv4, flow);
+	nfp_flower_compile_tun_ip_ext(&ext->ip_ext, &msk->ip_ext, flow);
+}
+
 static void
 nfp_flower_compile_ipv4_udp_tun(struct nfp_flower_ipv4_udp_tun *ext,
 				struct nfp_flower_ipv4_udp_tun *msk,
@@ -425,6 +454,21 @@ int nfp_flower_compile_flow_match(struct nfp_app *app,
 		msk += sizeof(struct nfp_flower_ipv6);
 	}
 
+	if (key_ls->key_layer_two & NFP_FLOWER_LAYER2_GRE) {
+		__be32 tun_dst;
+
+		nfp_flower_compile_ipv4_gre_tun((void *)ext, (void *)msk, flow);
+		tun_dst = ((struct nfp_flower_ipv4_gre_tun *)ext)->ipv4.dst;
+		ext += sizeof(struct nfp_flower_ipv4_gre_tun);
+		msk += sizeof(struct nfp_flower_ipv4_gre_tun);
+
+		/* Store the tunnel destination in the rule data.
+		 * This must be present and be an exact match.
+		 */
+		nfp_flow->nfp_tun_ipv4_addr = tun_dst;
+		nfp_tunnel_add_ipv4_off(app, tun_dst);
+	}
+
 	if (key_ls->key_layer & NFP_FLOWER_LAYER_VXLAN ||
 	    key_ls->key_layer_two & NFP_FLOWER_LAYER2_GENEVE) {
 		__be32 tun_dst;

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

@@ -52,8 +52,7 @@
 
 #define NFP_FLOWER_WHITELIST_TUN_DISSECTOR_R \
 	(BIT(FLOW_DISSECTOR_KEY_ENC_CONTROL) | \
-	 BIT(FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS) | \
-	 BIT(FLOW_DISSECTOR_KEY_ENC_PORTS))
+	 BIT(FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS))
 
 #define NFP_FLOWER_MERGE_FIELDS \
 	(NFP_FLOWER_LAYER_PORT | \
@@ -285,27 +284,51 @@ nfp_flower_calculate_key_layers(struct nfp_app *app,
 			return -EOPNOTSUPP;
 		}
 
-		flow_rule_match_enc_ports(rule, &enc_ports);
-		if (enc_ports.mask->dst != cpu_to_be16(~0)) {
-			NL_SET_ERR_MSG_MOD(extack, "unsupported offload: only an exact match L4 destination port is supported");
-			return -EOPNOTSUPP;
-		}
-
 		if (flow_rule_match_key(rule, FLOW_DISSECTOR_KEY_ENC_OPTS))
 			flow_rule_match_enc_opts(rule, &enc_op);
 
 
-		err = nfp_flower_calc_udp_tun_layer(enc_ports.key, enc_op.key,
-						    &key_layer_two, &key_layer,
-						    &key_size, priv, tun_type,
-						    extack);
-		if (err)
-			return err;
+		if (!flow_rule_match_key(rule, FLOW_DISSECTOR_KEY_ENC_PORTS)) {
+			/* check if GRE, which has no enc_ports */
+			if (netif_is_gretap(netdev)) {
+				*tun_type = NFP_FL_TUNNEL_GRE;
+				key_layer |= NFP_FLOWER_LAYER_EXT_META;
+				key_size += sizeof(struct nfp_flower_ext_meta);
+				key_layer_two |= NFP_FLOWER_LAYER2_GRE;
+				key_size +=
+					sizeof(struct nfp_flower_ipv4_gre_tun);
+
+				if (enc_op.key) {
+					NL_SET_ERR_MSG_MOD(extack, "unsupported offload: encap options not supported on GRE tunnels");
+					return -EOPNOTSUPP;
+				}
+			} else {
+				NL_SET_ERR_MSG_MOD(extack, "unsupported offload: an exact match on L4 destination port is required for non-GRE tunnels");
+				return -EOPNOTSUPP;
+			}
+		} else {
+			flow_rule_match_enc_ports(rule, &enc_ports);
+			if (enc_ports.mask->dst != cpu_to_be16(~0)) {
+				NL_SET_ERR_MSG_MOD(extack, "unsupported offload: only an exact match L4 destination port is supported");
+				return -EOPNOTSUPP;
+			}
 
-		/* Ensure the ingress netdev matches the expected tun type. */
-		if (!nfp_fl_netdev_is_tunnel_type(netdev, *tun_type)) {
-			NL_SET_ERR_MSG_MOD(extack, "unsupported offload: ingress netdev does not match the expected tunnel type");
-			return -EOPNOTSUPP;
+			err = nfp_flower_calc_udp_tun_layer(enc_ports.key,
+							    enc_op.key,
+							    &key_layer_two,
+							    &key_layer,
+							    &key_size, priv,
+							    tun_type, extack);
+			if (err)
+				return err;
+
+			/* Ensure the ingress netdev matches the expected
+			 * tun type.
+			 */
+			if (!nfp_fl_netdev_is_tunnel_type(netdev, *tun_type)) {
+				NL_SET_ERR_MSG_MOD(extack, "unsupported offload: ingress netdev does not match the expected tunnel type");
+				return -EOPNOTSUPP;
+			}
 		}
 	}