Plugin infrastructure improvements

This patch replaces requirement for vlib_plugin_register function
in the plugin so file and introduces new macro:

VLIB_PLUGIN_REGISTER () = {
  .version = "version string",
  .version_required = "requred version",
  .default_disabled = 1,
  .early_init = "early_init_function_name",
};

Plugin will nor be loaded if .default_disabled is set to 1
unless explicitely enabled in startup.conf.

If .verstion_required is set, plugin will not be loaded if there
is version mismatch between plugin and vpp. This can be bypassed
by setting "skip-version-check" for specific plugin.

If .early-init string is present, plugin loader will try to resolve
this specific symbol in the plugin namespace and make a function call.

Following startup.conf configuration is added:

plugins {
  path /path/to/plugin/directory
  plugin ila_plugin.so { enable skip-version-check }
  plugin acl_plugin.so { disable }
}

Change-Id: I706c691dd34d94ffe9e02b59831af8859a95f061
Signed-off-by: Damjan Marion <damarion@cisco.com>

2 files changed, 6 insertions, 22 deletions

diff --git a/src/plugins/snat/snat.c b/src/plugins/snat/snat.c
index 0fcd6ce8606..750cc925d7f 100644
--- a/src/plugins/snat/snat.c
+++ b/src/plugins/snat/snat.c
@@ -28,6 +28,7 @@
 #include <vlibapi/api.h>
 #include <vlibmemory/api.h>
 #include <vlibsocket/api.h>
+#include <vpp/app/version.h>
 
 snat_main_t snat_main;
 
@@ -129,27 +130,11 @@ VNET_FEATURE_INIT (ip4_snat_out2in_fast, static) = {
   .runs_before = VNET_FEATURES ("ip4-lookup"),
 };
 
-
-/* 
- * This routine exists to convince the vlib plugin framework that
- * we haven't accidentally copied a random .dll into the plugin directory.
- *
- * Also collects global variable pointers passed from the vpp engine
- */
-
-clib_error_t * 
-vlib_plugin_register (vlib_main_t * vm, vnet_plugin_handoff_t * h,
-                      int from_early_init)
-{
-  snat_main_t * sm = &snat_main;
-  clib_error_t * error = 0;
-
-  sm->vlib_main = vm;
-  sm->vnet_main = h->vnet_main;
-  sm->ethernet_main = h->ethernet_main;
-
-  return error;
-}
+/* *INDENT-OFF* */
+VLIB_PLUGIN_REGISTER () = {
+    .version = VPP_BUILD_VER,
+};
+/* *INDENT-ON* */
 
 /*$$$$$ move to an installed header file */
 #if (1 || CLIB_DEBUG > 0)       /* "trust, but verify" */
diff --git a/src/plugins/snat/snat.h b/src/plugins/snat/snat.h
index 32dc9f9e0a6..39cbd3f8e0f 100644
--- a/src/plugins/snat/snat.h
+++ b/src/plugins/snat/snat.h
@@ -233,7 +233,6 @@ typedef struct {
   vnet_main_t * vnet_main;
   ip4_main_t * ip4_main;
   ip_lookup_main_t * ip4_lookup_main;
-  ethernet_main_t * ethernet_main;  
   api_main_t * api_main;
 } snat_main_t;