IB/uverbs: Introduce a MPLS steering match filter

Add a new MPLS steering match filter that can match against
a single MPLS tag field.

Since the MPLS header can reside in different locations in the packet's
protocol stack as well as be encapsulated with a tunnel protocol, it
is required to know the exact location of the header in the protocol
stack.

Therefore, when including the MPLS protocol spec in the specs list,
it is mandatory to provide the list in an ordered manner, so
that it represents the actual header order in a matching packet.

Drivers that process the spec list and apply the matching rule
should treat the position of the MPLS spec in the spec list as the
actual location of the MPLS label in the packet's protocol stack.

Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Ariel Levkovich <lariel@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/uverbs_cmd.c

@@ -2959,6 +2959,17 @@ int ib_uverbs_kern_spec_to_ib_spec_filter(enum ib_flow_spec_type type,
 		memcpy(&ib_spec->gre.val, kern_spec_val, actual_filter_sz);
 		memcpy(&ib_spec->gre.mask, kern_spec_mask, actual_filter_sz);
 		break;
+	case IB_FLOW_SPEC_MPLS:
+		ib_filter_sz = offsetof(struct ib_flow_mpls_filter, real_sz);
+		actual_filter_sz = spec_filter_size(kern_spec_mask,
+						    kern_filter_sz,
+						    ib_filter_sz);
+		if (actual_filter_sz <= 0)
+			return -EINVAL;
+		ib_spec->mpls.size = sizeof(struct ib_flow_spec_mpls);
+		memcpy(&ib_spec->mpls.val, kern_spec_val, actual_filter_sz);
+		memcpy(&ib_spec->mpls.mask, kern_spec_mask, actual_filter_sz);
+		break;
 	default:
 		return -EINVAL;
 	}
@@ -3518,6 +3529,7 @@ int ib_uverbs_ex_create_flow(struct ib_uverbs_file *file,
 					   uflow_res);
 		if (err)
 			goto err_free;
+
 		flow_attr->size +=
 			((union ib_flow_spec *) ib_spec)->size;
 		cmd.flow_attr.size -= ((struct ib_uverbs_flow_spec *)kern_spec)->size;

include/rdma/ib_verbs.h

@@ -1853,6 +1853,7 @@ enum ib_flow_spec_type {
 	IB_FLOW_SPEC_UDP		= 0x41,
 	IB_FLOW_SPEC_VXLAN_TUNNEL	= 0x50,
 	IB_FLOW_SPEC_GRE		= 0x51,
+	IB_FLOW_SPEC_MPLS		= 0x60,
 	IB_FLOW_SPEC_INNER		= 0x100,
 	/* Actions */
 	IB_FLOW_SPEC_ACTION_TAG         = 0x1000,
@@ -2010,6 +2011,19 @@ struct ib_flow_spec_gre {
 	struct ib_flow_gre_filter     mask;
 };
 
+struct ib_flow_mpls_filter {
+	__be32 tag;
+	/* Must be last */
+	u8	real_sz[0];
+};
+
+struct ib_flow_spec_mpls {
+	u32                           type;
+	u16			      size;
+	struct ib_flow_mpls_filter     val;
+	struct ib_flow_mpls_filter     mask;
+};
+
 struct ib_flow_spec_action_tag {
 	enum ib_flow_spec_type	      type;
 	u16			      size;
@@ -2040,6 +2054,7 @@ union ib_flow_spec {
 	struct ib_flow_spec_tunnel      tunnel;
 	struct ib_flow_spec_esp		esp;
 	struct ib_flow_spec_gre		gre;
+	struct ib_flow_spec_mpls	mpls;
 	struct ib_flow_spec_action_tag  flow_tag;
 	struct ib_flow_spec_action_drop drop;
 	struct ib_flow_spec_action_handle action;