Fix bug in IP wildcarding.

    According to the OpenFlow specification, the mask on nw_src and nw_dst
    fields is not a description of how many bits to match, but rather a
    description of how many bits to mask. Hence, /0 is exact match and /32
    is a total wildcard.

    We had this backwards in the OpenFlow0x01 controller.

    This pull requests fixes the bug.

Author: jnfoster

lib/SDN_OpenFlow0x01.ml

@@ -49,12 +49,22 @@ let from_pattern (pat : AL.Pattern.t) : Core.pattern =
   ; Core.dlVlanPcp = pat.AL.Pattern.dlVlanPcp
   ; Core.nwSrc = (match pat.AL.Pattern.nwSrc with
     | None   -> None
-    | Some (p,m) -> let mo = if m = 32l then None else Some m in
+    | Some (p,m) ->
+       let mo = 
+	 if m = 32l then 
+	   None 
+	 else 
+	   Some (Int32.sub 32l m) in
       Some { Core.m_value = p; Core.m_mask = mo })
   ; Core.nwDst = (match pat.AL.Pattern.nwDst with
     | None   -> None
-    | Some (p,m) -> let mo = if m = 32l then None else Some m in
-      Some { Core.m_value = p; Core.m_mask = mo })
+    | Some (p,m) ->
+       let mo = 
+	 if m = 32l then 
+	   None 
+	 else 
+	   Some (Int32.sub 32l m) in
+       Some { Core.m_value = p; Core.m_mask = mo })
   ; Core.nwProto = pat.AL.Pattern.nwProto
   ; Core.nwTos = None
   ; Core.tpSrc = pat.AL.Pattern.tpSrc