nfp: flower: fix unsupported pre_tunnel flows

There are some pre_tunnel flows combinations which are incorrectly being
offloaded without proper support, fix these.

- Matching on MPLS is not supported for pre_tun.
- Match on IPv4/IPv6 layer must be present.
- Destination MAC address must match pre_tun.dev MAC

Fixes: 120ffd84 ("nfp: flower: verify pre-tunnel rules")
Signed-off-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -1142,6 +1142,12 @@ nfp_flower_validate_pre_tun_rule(struct nfp_app *app,
 		return -EOPNOTSUPP;
 	}
 
+	if (!(key_layer & NFP_FLOWER_LAYER_IPV4) &&
+	    !(key_layer & NFP_FLOWER_LAYER_IPV6)) {
+		NL_SET_ERR_MSG_MOD(extack, "unsupported pre-tunnel rule: match on ipv4/ipv6 eth_type must be present");
+		return -EOPNOTSUPP;
+	}
+
 	/* Skip fields known to exist. */
 	mask += sizeof(struct nfp_flower_meta_tci);
 	ext += sizeof(struct nfp_flower_meta_tci);
@@ -1152,6 +1158,13 @@ nfp_flower_validate_pre_tun_rule(struct nfp_app *app,
 	mask += sizeof(struct nfp_flower_in_port);
 	ext += sizeof(struct nfp_flower_in_port);
 
+	/* Ensure destination MAC address matches pre_tun_dev. */
+	mac = (struct nfp_flower_mac_mpls *)ext;
+	if (memcmp(&mac->mac_dst[0], flow->pre_tun_rule.dev->dev_addr, 6)) {
+		NL_SET_ERR_MSG_MOD(extack, "unsupported pre-tunnel rule: dest MAC must match output dev MAC");
+		return -EOPNOTSUPP;
+	}
+
 	/* Ensure destination MAC address is fully matched. */
 	mac = (struct nfp_flower_mac_mpls *)mask;
 	if (!is_broadcast_ether_addr(&mac->mac_dst[0])) {
@@ -1159,6 +1172,11 @@ nfp_flower_validate_pre_tun_rule(struct nfp_app *app,
 		return -EOPNOTSUPP;
 	}
 
+	if (mac->mpls_lse) {
+		NL_SET_ERR_MSG_MOD(extack, "unsupported pre-tunnel rule: MPLS not supported");
+		return -EOPNOTSUPP;
+	}
+
 	mask += sizeof(struct nfp_flower_mac_mpls);
 	ext += sizeof(struct nfp_flower_mac_mpls);
 	if (key_layer & NFP_FLOWER_LAYER_IPV4 ||