gre: improve .api descriptions

+ Remove fields not present in the typedef.
+ Sort field descriptions by the order in the typedef.
+ Add descriptions to other messages.
+ Add comment lines with de-abbreviated enum values.

Type: style

Change-Id: I2c41e0204ba5c59a53f1cf7b5837118484a16ad0
Signed-off-by: Vratko Polak <vrpolak@cisco.com>

src/vnet/gre/gre.api

@@ -25,22 +25,22 @@ import "vnet/ip/ip_types.api";
 enum gre_tunnel_type : u8
 {
   GRE_API_TUNNEL_TYPE_L3 = 0,
+  /* L2 Transparent Ethernet Bridge */
   GRE_API_TUNNEL_TYPE_TEB,
+  /* Encapsulated Remote Switched Port ANalyzer */
   GRE_API_TUNNEL_TYPE_ERSPAN,
 };
 
-/** \brief A GRE tunnel
-    @param client_index - opaque cookie to identify the sender
-    @param context - sender context, to match reply w/ request
-    @param tunnel_type - 0: L3, 1: TEB, 2: ERSPAN
-    @param instance - optional unique custom device instance, else ~0.
+/** \brief A composite type uniquely defining a GRE tunnel.
+    @param type - tunnel type (see enum definition), 0: L3, 1: TEB, 2: ERSPAN
     @param mode - P2P or P2MP
     @param flags - to control encap/decap behaviour
-    @param src - Source IP address
-    @param dst - Destination IP address, can be multicast
-    @param outer_table_id - Encap FIB table ID
     @param session_id - session for ERSPAN tunnel, range 0-1023
+    @param instance - optional unique custom device instance, else ~0.
+    @param outer_table_id - Encap FIB table ID
     @param sw_if_index - ignored on create/delete, present in details.
+    @param src - Source IP address
+    @param dst - Destination IP address, can be multicast
 */
 typedef gre_tunnel
 {
@@ -55,6 +55,12 @@ typedef gre_tunnel
   vl_api_address_t dst;
 };
 
+/** \brief Add or delete a single GRE tunnel.
+    @param client_index - opaque cookie to identify the sender.
+    @param context - sender context, to match reply w/ request.
+    @param is_add - add if true, delete if false.
+    @param tunnel - tunnel definition to add or delete.
+*/
 define gre_tunnel_add_del
 {
   u32 client_index;
@@ -63,20 +69,34 @@ define gre_tunnel_add_del
   vl_api_gre_tunnel_t tunnel;
 };
 
+/** \brief Add or delete a single GRE tunnel.
+    @param context - sender context, to match reply w/ request.
+    @param retval - return code for the request.
+    @param sw_if_index - the interface corresponding to the affected tunnel.
+*/
 define gre_tunnel_add_del_reply
 {
   u32 context;
   i32 retval;
   vl_api_interface_index_t sw_if_index;
 };
 
+/** \brief Dump details of all or just a single GRE tunnel.
+    @param client_index - opaque cookie to identify the sender.
+    @param context - sender context, to match reply w/ request.
+    @param sw_if_index - filter for tunnel of this interface index, ~0 for all.
+*/
 define gre_tunnel_dump
 {
   u32 client_index;
   u32 context;
   vl_api_interface_index_t sw_if_index;
 };
 
+/** \brief Details response for one of the requested GRE tunnels.
+    @param context - sender context, to match reply w/ request.
+    @param tunnel - definition of the dumped tunnel.
+*/
 define gre_tunnel_details
 {
   u32 context;