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, 6 insertions, 12 deletions

diff --git a/src/plugins/http_static/http_static.api b/src/plugins/http_static/http_static.api
index dc3dcac71ba..4d6d8bfe9b5 100644
--- a/src/plugins/http_static/http_static.api
+++ b/src/plugins/http_static/http_static.api
@@ -2,7 +2,7 @@
 /** \file
     This file defines static http server control-plane API messages
 */
-option version = "2.0.0";
+option version = "2.1.0";
 
 /** \brief Configure and enable the static http server
     @param client_index - opaque cookie to identify the sender
@@ -29,7 +29,7 @@ autoreply define http_static_enable {
     u32 private_segment_size;
 
     /* Root of the html path */
-    string www_root[limit=256];
+    string www_root[256];
     /* The bind URI */
-    string uri[limit=256];
+    string uri[256];
 };
diff --git a/src/plugins/http_static/http_static.c b/src/plugins/http_static/http_static.c
index 2ad4acfb0c1..6000cf62219 100644
--- a/src/plugins/http_static/http_static.c
+++ b/src/plugins/http_static/http_static.c
@@ -66,22 +66,16 @@ static void vl_api_http_static_enable_t_handler
   vl_api_http_static_enable_reply_t *rmp;
   http_static_main_t *hmp = &http_static_main;
   int rv;
-  u8 *www_root = 0;
-  u8 *uri = 0;
 
-  char *p = (char *) &mp->www_root;
-  www_root = vl_api_from_api_to_vec ((vl_api_string_t *) p);
-  p += vl_api_string_len ((vl_api_string_t *) p) + sizeof (vl_api_string_t);
-  uri = vl_api_from_api_to_vec ((vl_api_string_t *) p);
+  mp->uri[ARRAY_LEN (mp->uri) - 1] = 0;
+  mp->www_root[ARRAY_LEN (mp->www_root) - 1] = 0;
 
   rv = http_static_server_enable_api
     (ntohl (mp->fifo_size),
      ntohl (mp->cache_size_limit),
      ntohl (mp->prealloc_fifos),
-     ntohl (mp->private_segment_size), www_root, uri);
+     ntohl (mp->private_segment_size), mp->www_root, mp->uri);
 
-  vec_free (www_root);
-  vec_free (uri);
   REPLY_MACRO (VL_API_HTTP_STATIC_ENABLE_REPLY);
 }