multi: keep track of xids in ChunkController

The ChunkController keeps track of a per-connection xid that users can
use to generate new xids.

Author: seliopou

async/Async_OpenFlow.mli

@@ -162,6 +162,7 @@ module Chunk : sig
     ]
 
     val client_version : t -> Client_id.t -> int
+    val client_next_xid : t -> Client_id.t -> int32
 
     val send_txn
       :  t
@@ -191,7 +192,7 @@ module OpenFlow0x01 : sig
     val send_txn
       :  t
       -> Client_id.t
-      -> m
+      -> OpenFlow0x01.Message.t
       -> [ `Sent of Message.t Ivar.t | `Drop of exn ] Deferred.t
   end
 
@@ -214,7 +215,7 @@ module OpenFlow0x04 : sig
     val send_txn
       :  t
       -> Client_id.t
-      -> m
+      -> OpenFlow0x04.Message.t
       -> [ `Sent of Message.t Ivar.t | `Drop of exn ] Deferred.t
   end
 

async/Async_OpenFlow0x01.ml

@@ -96,7 +96,8 @@ module Controller = struct
 
   let send_txn t sw_id msg =
     let c_id = client_id_of_switch_exn t sw_id in
-    ChunkController.send_txn t.sub c_id (Message.marshal' msg)
+    let xid  = ChunkController.client_next_xid t.sub c_id in
+    ChunkController.send_txn t.sub c_id (Message.marshal' (xid, msg))
 
   let send_ignore_errors t sw_id msg =
     let c_id = client_id_of_switch_exn t sw_id in

async/Async_OpenFlow0x04.ml

@@ -131,7 +131,8 @@ module Controller = struct
 
   let send_txn t sw_id msg =
     let c_id = client_id_of_switch_exn t sw_id in
-    ChunkController.send_txn t.sub c_id (Message.marshal' msg)
+    let xid  = ChunkController.client_next_xid t.sub c_id in
+    ChunkController.send_txn t.sub c_id (Message.marshal' (xid, msg))
 
   let send_ignore_errors t sw_id msg =
     let c_id = client_id_of_switch_exn t sw_id in

async/Async_OpenFlowChunk.ml

@@ -47,6 +47,7 @@ module Controller = struct
     type t = {
       state : [ `Active | `Idle | `Kill ];
       version : int option;
+      mutable xid : int32;
       txns : r Ivar.t XidTbl.t;
       state_entered : Time.t;
       last_activity : Time.t
@@ -56,11 +57,17 @@ module Controller = struct
       let now = Time.now () in
       { state = `Active
       ; version = None
+      ; xid = 1l
       ; txns = XidTbl.create ()
       ; state_entered = now
       ; last_activity = now
       }
 
+    let next_xid (t:t) =
+      let xid = t.xid in
+      t.xid <- Int32.(xid + 1l);
+      xid
+
     let add_txn (t:t) m =
       let xid = (Message.header_of m).OpenFlow_Header.xid in
       let ivar = ref None in
@@ -266,6 +273,9 @@ module Controller = struct
     | None      -> raise Not_found
     | Some(ver) -> ver
 
+  let client_next_xid t c_id =
+    Conn.next_xid (Client_id.Table.find_exn t.clients c_id)
+
   let handshake v t evt =
     let open Header in
     match evt with