tap: Move client registration check to top

Type: fix

Change-Id: I33dc4cf7b6c69f74c7bf4971ce59442678b878ef
Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>
diff --git a/src/vnet/devices/tap/tapv2.api b/src/vnet/devices/tap/tapv2.api
index dee7304..c11a07c 100644
--- a/src/vnet/devices/tap/tapv2.api
+++ b/src/vnet/devices/tap/tapv2.api
@@ -55,7 +55,7 @@
 {
   u32 client_index;
   u32 context;
-  u32 id;
+  u32 id [default= 0xffffffff] ;
   u8 use_random_mac;
   u8 mac_address[6];
   u16 tx_ring_sz; /* optional, default is 256 entries, must be power of 2 */
diff --git a/src/vnet/devices/tap/tapv2_api.c b/src/vnet/devices/tap/tapv2_api.c
index 2471d00..a1acacf 100644
--- a/src/vnet/devices/tap/tapv2_api.c
+++ b/src/vnet/devices/tap/tapv2_api.c
@@ -52,10 +52,15 @@
 static void
 vl_api_tap_create_v2_t_handler (vl_api_tap_create_v2_t * mp)
 {
+  vl_api_registration_t *reg;
+  reg = vl_api_client_index_to_registration (mp->client_index);
+  if (!reg)
+    return;
+
   vnet_main_t *vnm = vnet_get_main ();
   vlib_main_t *vm = vlib_get_main ();
   vl_api_tap_create_v2_reply_t *rmp;
-  vl_api_registration_t *reg;
+
   tap_create_if_args_t _a, *ap = &_a;
 
   clib_memset (ap, 0, sizeof (*ap));
@@ -119,9 +124,6 @@
 
   tap_create_if (vm, ap);
 
-  reg = vl_api_client_index_to_registration (mp->client_index);
-  if (!reg)
-    return;;
 
   /* If a tag was supplied... */
   if (mp->tag[0])
@@ -145,18 +147,21 @@
 static void
 vl_api_tap_delete_v2_t_handler (vl_api_tap_delete_v2_t * mp)
 {
+  vl_api_registration_t *reg;
+  reg = vl_api_client_index_to_registration (mp->client_index);
+  if (!reg)
+    return;
+
   vnet_main_t *vnm = vnet_get_main ();
   vlib_main_t *vm = vlib_get_main ();
   int rv;
   vl_api_tap_delete_v2_reply_t *rmp;
-  vl_api_registration_t *reg;
+
   u32 sw_if_index = ntohl (mp->sw_if_index);
 
   rv = tap_delete_if (vm, sw_if_index);
 
-  reg = vl_api_client_index_to_registration (mp->client_index);
-  if (!reg)
-    return;
+
 
   rmp = vl_msg_api_alloc (sizeof (*rmp));
   rmp->_vl_msg_id = ntohs (VL_API_TAP_DELETE_V2_REPLY);