api: enforce vla is last and fixed string type

Enforce that variable length fields are the last element of API messages.

Add a 'fixed' version of string type, since dealing with
multiple variable length strings turned out too painful
for the C language bindings.

The string type is now:
{
  string name[64]; // NUL terminated C-string. Essentially decays to u8 name[64]
  string name[];   // Variable length string with embedded len field (vl_api_string_t)
};

The latter notation could be made available to other types as well.
e.g.
{
  vl_api_address_t addresses[];
}
instead of

{
  u32 n_addr;
  vl_api_address_t addresses[n_addr];
};

Type: fix
Change-Id: I18fa17ef47227633752ab50453e8d20a652a9f9b
Signed-off-by: Ole Troan <ot@cisco.com>

2 files changed, 8 insertions, 9 deletions

diff --git a/src/plugins/map/map.api b/src/plugins/map/map.api
index b15b38a3d19..b1f78124c2c 100644
--- a/src/plugins/map/map.api
+++ b/src/plugins/map/map.api
@@ -13,7 +13,7 @@
  * limitations under the License.
  */
 
-option version = "4.0.0";
+option version = "4.1.0";
 
 import "vnet/ip/ip_types.api";
 
@@ -40,7 +40,7 @@ define map_add_domain
   u8 psid_offset;
   u8 psid_length;
   u16 mtu;
-  string tag[limit=64];
+  string tag[64];
 };
 
 /** \brief Reply for MAP domain add
@@ -121,7 +121,7 @@ define map_domain_details
   u8 psid_length;
   u8 flags;
   u16 mtu;
-  string tag[limit=64];
+  string tag[64];
 };
 
 define map_rule_dump
diff --git a/src/plugins/map/map_api.c b/src/plugins/map/map_api.c
index 1e50ba1b714..394ec243dbf 100644
--- a/src/plugins/map/map_api.c
+++ b/src/plugins/map/map_api.c
@@ -53,8 +53,8 @@ vl_api_map_add_domain_t_handler (vl_api_map_add_domain_t * mp)
   int rv = 0;
   u32 index;
   u8 flags = 0;
-  u8 *vtag = 0;
-  vtag = vl_api_from_api_to_vec (&mp->tag);
+
+  u8 *tag = format (0, "%s", mp->tag);
   rv =
     map_create_domain ((ip4_address_t *) & mp->ip4_prefix.address,
 		       mp->ip4_prefix.len,
@@ -62,9 +62,8 @@ vl_api_map_add_domain_t_handler (vl_api_map_add_domain_t * mp)
 		       mp->ip6_prefix.len,
 		       (ip6_address_t *) & mp->ip6_src.address,
 		       mp->ip6_src.len, mp->ea_bits_len, mp->psid_offset,
-		       mp->psid_length, &index, ntohs (mp->mtu), flags, vtag);
-  vec_free (vtag);
-
+		       mp->psid_length, &index, ntohs (mp->mtu), flags, tag);
+  vec_free (tag);
   /* *INDENT-OFF* */
   REPLY_MACRO2(VL_API_MAP_ADD_DOMAIN_REPLY,
   ({
@@ -140,7 +139,7 @@ vl_api_map_domain_dump_t_handler (vl_api_map_domain_dump_t * mp)
     rmp->flags = d->flags;
     rmp->mtu = htons(d->mtu);
 
-    vl_api_vec_to_api_string (de->tag, &rmp->tag );
+    strncpy ((char *) rmp->tag, (char *) de->tag, ARRAY_LEN(rmp->tag)-1);
 
     vl_api_send_msg (reg, (u8 *) rmp);
   }));