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>
(cherry picked from commit e5ff5a36dd126ee57dca4e0b03da2f7704e0a4f5)
Signed-off-by: Ole Troan <ot@cisco.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/plugins/nat/test/test_nat.py b/src/plugins/nat/test/test_nat.py
index 773eb51d4ee..2e062f156c2 100644
--- a/src/plugins/nat/test/test_nat.py
+++ b/src/plugins/nat/test/test_nat.py
@@ -1893,7 +1893,7 @@ class TestNAT44(MethodHolder):
             is_add=1)
         sm = self.vapi.nat44_static_mapping_dump()
         self.assertEqual(len(sm), 1)
-        self.assertEqual((sm[0].tag).split(b'\0', 1)[0], b'')
+        self.assertEqual(sm[0].tag, '')
         self.assertEqual(sm[0].protocol, 0)
         self.assertEqual(sm[0].local_port, 0)
         self.assertEqual(sm[0].external_port, 0)