nfp: fix supported key layers calculation

Previously when calculating the supported key layers MPLS, IPv4/6
TTL and TOS were not considered. This patch checks that the TTL and
TOS fields are masked out before offloading. Additionally this patch
checks that MPLS packets are correctly handled, by not offloading them.

Fixes: af9d842c ("nfp: extend flower add flow offload")
Signed-off-by: NPieter Jansen van Vuuren <pieter.jansenvanvuuren@netronome.com>
Reviewed-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: NSimon Horman <simon.horman@netronome.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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

@@ -107,6 +107,7 @@ nfp_flower_calculate_key_layers(struct nfp_fl_key_ls *ret_key_ls,
 {
 	struct flow_dissector_key_basic *mask_basic = NULL;
 	struct flow_dissector_key_basic *key_basic = NULL;
+	struct flow_dissector_key_ip *mask_ip = NULL;
 	u32 key_layer_two;
 	u8 key_layer;
 	int key_size;
@@ -132,6 +133,11 @@ nfp_flower_calculate_key_layers(struct nfp_fl_key_ls *ret_key_ls,
 						      flow->key);
 	}
 
+	if (dissector_uses_key(flow->dissector, FLOW_DISSECTOR_KEY_IP))
+		mask_ip = skb_flow_dissector_target(flow->dissector,
+						    FLOW_DISSECTOR_KEY_IP,
+						    flow->mask);
+
 	key_layer_two = 0;
 	key_layer = NFP_FLOWER_LAYER_PORT | NFP_FLOWER_LAYER_MAC;
 	key_size = sizeof(struct nfp_flower_meta_one) +
@@ -142,11 +148,19 @@ nfp_flower_calculate_key_layers(struct nfp_fl_key_ls *ret_key_ls,
 		/* Ethernet type is present in the key. */
 		switch (key_basic->n_proto) {
 		case cpu_to_be16(ETH_P_IP):
+			if (mask_ip && mask_ip->tos)
+				return -EOPNOTSUPP;
+			if (mask_ip && mask_ip->ttl)
+				return -EOPNOTSUPP;
 			key_layer |= NFP_FLOWER_LAYER_IPV4;
 			key_size += sizeof(struct nfp_flower_ipv4);
 			break;
 
 		case cpu_to_be16(ETH_P_IPV6):
+			if (mask_ip && mask_ip->tos)
+				return -EOPNOTSUPP;
+			if (mask_ip && mask_ip->ttl)
+				return -EOPNOTSUPP;
 			key_layer |= NFP_FLOWER_LAYER_IPV6;
 			key_size += sizeof(struct nfp_flower_ipv6);
 			break;
@@ -157,6 +171,11 @@ nfp_flower_calculate_key_layers(struct nfp_fl_key_ls *ret_key_ls,
 		case cpu_to_be16(ETH_P_ARP):
 			return -EOPNOTSUPP;
 
+		/* Currently we do not offload MPLS. */
+		case cpu_to_be16(ETH_P_MPLS_UC):
+		case cpu_to_be16(ETH_P_MPLS_MC):
+			return -EOPNOTSUPP;
+
 		/* Will be included in layer 2. */
 		case cpu_to_be16(ETH_P_8021Q):
 			break;