flowstats: combine types for indvidual/aggregate stats request

Eliminate code duplication in the representation, parsing, and
marshalling of individual and aggregate stats requests. Both requests
have the same fields, and the fields behave in the same way

Author: seliopou

lib/OpenFlow0x01.ml

@@ -1713,49 +1713,30 @@ module StatsRequest = struct
     match msg with
     | DescriptionRequest -> sizeof_ofp_stats_request
     | FlowTableStatsRequest -> sizeof_ofp_stats_request
-    | IndividualRequest flow_req ->
-      marshal_flow_stats_request flow_req.is_of_match flow_req.is_out_port flow_req.is_table_id out'
-    | AggregateRequest agg_req ->
-      marshal_flow_stats_request agg_req.as_of_match agg_req.as_out_port agg_req.as_table_id out'
+    | IndividualRequest stats_req
+    | AggregateRequest  stats_req ->
+      marshal_flow_stats_request stats_req.sr_of_match stats_req.sr_out_port stats_req.sr_table_id out'
 
-  let parse_flow_stats_request bits =
-    let is_of_match = Match.parse (get_ofp_flow_stats_request_of_match bits) in
-    let is_table_id = get_ofp_flow_stats_request_table_id bits in
-    let is_out_port =
+  let parse_stats_request bits =
+    let sr_of_match = Match.parse (get_ofp_flow_stats_request_of_match bits) in
+    let sr_table_id = get_ofp_flow_stats_request_table_id bits in
+    let sr_out_port =
       (let open PseudoPort in
       if ofp_port_to_int OFPP_NONE = (get_ofp_flow_stats_request_out_port bits) then
         None
       else
         Some (PhysicalPort (get_ofp_flow_stats_request_out_port bits)))
     in
-    { is_of_match = is_of_match;
-      is_table_id = is_table_id;
-      is_out_port = is_out_port
-    }
+    { sr_of_match; sr_table_id; sr_out_port }
 
-  let parse_aggregate_stats_request bits =
-    let as_of_match = Match.parse (get_ofp_flow_stats_request_of_match bits) in
-    let as_table_id = get_ofp_flow_stats_request_table_id bits in
-    let as_out_port =
-      (let open PseudoPort in
-      if ofp_port_to_int OFPP_NONE = (get_ofp_flow_stats_request_out_port bits) then
-        None
-      else
-        Some (PhysicalPort (get_ofp_flow_stats_request_out_port bits)))
-    in
-    { as_of_match = as_of_match;
-      as_table_id = as_table_id;
-      as_out_port = as_out_port
-    }
-  
   let parse bits =
     let stats_type_code = get_ofp_stats_request_req_type bits in
     let body = Cstruct.shift bits sizeof_ofp_stats_request in
     match int_to_ofp_stats_types stats_type_code with
     | Some OFPST_DESC -> DescriptionRequest
     | Some OFPST_TABLE -> FlowTableStatsRequest
-    | Some OFPST_FLOW -> IndividualRequest (parse_flow_stats_request body)
-    | Some OFPST_AGGREGATE -> AggregateRequest (parse_aggregate_stats_request body)
+    | Some OFPST_FLOW -> IndividualRequest (parse_stats_request body)
+    | Some OFPST_AGGREGATE -> AggregateRequest (parse_stats_request body)
     | Some OFPST_QUEUE -> raise (Unparsable "queue statistics unsupported")
     | Some OFPST_VENDOR -> raise (Unparsable "vendor statistics unsupported")
     | Some OFPST_PORT -> raise (Unparsable "port statistics unsupported")

lib/OpenFlow0x01_Stats.ml

@@ -1,23 +1,17 @@
 open Packet
 open OpenFlow0x01_Core
 
-type individualStatsReq =
-  { is_of_match : pattern
-  ; is_table_id : int8
-  ; is_out_port : pseudoPort option 
-  }
-
-type aggregateStatsReq =
-  { as_of_match : pattern
-  ; as_table_id : int8
-  ; as_out_port : pseudoPort option
+type statsReq =
+  { sr_of_match : pattern
+  ; sr_table_id : int8
+  ; sr_out_port : pseudoPort option
   }
 
 type request =
   | DescriptionRequest
   | FlowTableStatsRequest
-  | IndividualRequest of individualStatsReq
-  | AggregateRequest of aggregateStatsReq
+  | IndividualRequest of statsReq
+  | AggregateRequest of statsReq
 
 type descriptionStats =
     { manufacturer : string

lib/OpenFlow0x01_Stats.mli

@@ -7,25 +7,18 @@ open OpenFlow0x01_Core
     entries to have this as an output port.  Use table ID [0xFF] to
     read from all tables. *)
 
-(** The body of an individual flow stat request. *)
-type individualStatsReq =
-  { is_of_match : pattern
-  ; is_table_id : int8
-  ; is_out_port : pseudoPort option
-  }
-
-(** The body of an aggregate flow stat request. *)
-type aggregateStatsReq =
-  { as_of_match : pattern
-  ; as_table_id : int8
-  ; as_out_port : pseudoPort option
+(** The body of an individual or aggregate flow stat request. *)
+type statsReq =
+  { sr_of_match : pattern
+  ; sr_table_id : int8
+  ; sr_out_port : pseudoPort option
   }
 
 type request =
   | DescriptionRequest
   | FlowTableStatsRequest
-  | IndividualRequest of individualStatsReq
-  | AggregateRequest of aggregateStatsReq
+  | IndividualRequest of statsReq
+  | AggregateRequest of statsReq
 
   (** The body of a reply to a description request. *)
 type descriptionStats =