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>

1 files changed, 6 insertions, 12 deletions

diff --git a/src/plugins/ioam/encap/ip6_ioam_trace.c b/src/plugins/ioam/encap/ip6_ioam_trace.c
index 3a6758cd859..a836dfe817b 100644
--- a/src/plugins/ioam/encap/ip6_ioam_trace.c
+++ b/src/plugins/ioam/encap/ip6_ioam_trace.c
@@ -16,6 +16,7 @@
 #include <vnet/vnet.h>
 #include <vnet/pg/pg.h>
 #include <vppinfra/error.h>
+#include <vpp/app/version.h>
 
 #include <vnet/ip/ip6.h>
 #include <vnet/ip/ip6_hop_by_hop.h>
@@ -349,18 +350,11 @@ VLIB_CLI_COMMAND (ip6_show_ioam_trace_cmd, static) = {
 };
 /* *INDENT-ON* */
 
-/*
- * 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)
-{
-  return 0;
-}
+/* *INDENT-OFF* */
+VLIB_PLUGIN_REGISTER () = {
+    .version = VPP_BUILD_VER,
+};
+/* *INDENT-ON* */
 
 static clib_error_t *
 ip6_hop_by_hop_ioam_trace_init (vlib_main_t * vm)