Add #define-s for message target types

OVS_GENL_TARGET_TO_INDEX: will be used by message verification, when
we will use arrays instead of switch cases.

Signed-off-by: Samuel Ghinet <sghinet@cloudbasesolutions.com>
Add debug macro: EXPECT

Check a boolean expression, and if its value is FALSE, it calls OVS_CHECK_RET.
The usage of EXPECT will shorten the code, making it clearer.

Signed-off-by: Samuel Ghinet <sghinet@cloudbasesolutions.com>
Add macro: OVS_FOR_EACH_ARG

A more concise way to loop over the OVS_ARGUMENT-s of an OVS_ARGUMENT_GROUP

Signed-off-by: Samuel Ghinet <sghinet@cloudbasesolutions.com>
Add utility macros & functions for arg types

o) converting an arg type to an index within its group
o) retrieving the first or last arg type within a group
o) counting arg types within a group

These changes will be useful when doing arg verification
using arrays, instead of switch cases.

Signed-off-by: Samuel Ghinet <sghinet@cloudbasesolutions.com>
Move msg verification functions to new files

From Message.c/.h to MsgVerification.c/.h.
This way, we will achieve better clarity by having a lesser number
of lines of code in Message.c + we will have msg verification
functions in dedicated files

Signed-off-by: Samuel Ghinet <sghinet@cloudbasesolutions.com>
Move several funcs from ArgVerification

to MsgVerification.
These are functions that are used in MsgVerification only.

Signed-off-by: Samuel Ghinet <sghinet@cloudbasesolutions.com>
Rename funcs in MsgVerification

In order to provide better clarity over their functionality.
Also, some of these functions no longer need to be public
(i.e. declared in .h file).

Signed-off-by: Samuel Ghinet <sghinet@cloudbasesolutions.com>
Refactor arg & msg verification

Use arrays instead of switch cases, wherever possible.
This provides a clearer and more concise verification code.

Signed-off-by: Samuel Ghinet <sghinet@cloudbasesolutions.com>