acl-plugin: VPP-1230: fix the "undefined symbol" error for acl_main when using the inline functions

The acl_main struct, which is defined in the acl_plugin, is not visible when
the ACL plugin inline code is being compiled within the context of other plugins.
Fix that by using the global pointer variable, which exists in both the ACL plugin
context and is set in the context of the external plugins using ACL plugin.

Change-Id: Iaa74dd8cf36ff5442a06a25c5c968722116bddf8
Signed-off-by: Andrew Yourtchenko <ayourtch@gmail.com>
(cherry picked from commit 1286a15a6e60f80b0e1b349f876de8fa38c71368)

3 files changed, 31 insertions, 9 deletions

diff --git a/src/plugins/acl/acl.c b/src/plugins/acl/acl.c
index 90b369e3296..7d3a8527eac 100644
--- a/src/plugins/acl/acl.c
+++ b/src/plugins/acl/acl.c
@@ -54,6 +54,7 @@
 #include "public_inlines.h"
 
 acl_main_t acl_main;
+acl_main_t *p_acl_main = &acl_main;
 
 #define REPLY_MSG_ID_BASE am->msg_id_base
 #include <vlibapi/api_helper_macros.h>
diff --git a/src/plugins/acl/acl.h b/src/plugins/acl/acl.h
index 7af5b201551..8e7c80076f6 100644
--- a/src/plugins/acl/acl.h
+++ b/src/plugins/acl/acl.h
@@ -362,6 +362,13 @@ AH has a special treatment of its length, it is in 32-bit words, not 64-bit word
 
 
 extern acl_main_t acl_main;
+/*
+ * pointer to the above.
+ * Needed for some gymnastics to be able to provide
+ * the inline functions from this plugin to other plugins.
+ */
+
+extern acl_main_t *p_acl_main;
 
 void *acl_plugin_set_heap();
 
diff --git a/src/plugins/acl/public_inlines.h b/src/plugins/acl/public_inlines.h
index f4942ec1a24..e7e47c4b561 100644
--- a/src/plugins/acl/public_inlines.h
+++ b/src/plugins/acl/public_inlines.h
@@ -26,6 +26,19 @@
 /* check if a given ACL exists */
 
 #ifdef ACL_PLUGIN_EXTERNAL_EXPORTS
+
+/*
+ * Define a pointer to the acl_main which will be filled during the initialization.
+ */
+acl_main_t *p_acl_main = 0;
+
+/*
+ * If the file is included more than once, the symbol collision will make the problem obvious.
+ * If the include is done only once, it is just a lonely null var
+ * sitting around.
+ */
+void *ERROR_ACL_PLUGIN_EXPORTS_FILE_MUST_BE_INCLUDED_ONLY_IN_ONE_PLACE = 0;
+
 u8 (*acl_plugin_acl_exists) (u32 acl_index);
 #else
 u8 acl_plugin_acl_exists (u32 acl_index);
@@ -128,18 +141,19 @@ acl_plugin_match_5tuple_inline (u32 lc_index,
 
 #ifdef ACL_PLUGIN_EXTERNAL_EXPORTS
 
-#define LOAD_SYMBOL_FROM_PLUGIN(p, s)                                     \
+#define LOAD_SYMBOL_FROM_PLUGIN_TO(p, s, st)                              \
 ({                                                                        \
-    s = vlib_get_plugin_symbol(p, #s);                                    \
-    if (!s)                                                               \
+    st = vlib_get_plugin_symbol(p, #s);                                    \
+    if (!st)                                                               \
         return clib_error_return(0,                                       \
                 "Plugin %s and/or symbol %s not found.", p, #s);          \
 })
 
-#define LOAD_SYMBOL(s) LOAD_SYMBOL_FROM_PLUGIN("acl_plugin.so", s)
+#define LOAD_SYMBOL(s) LOAD_SYMBOL_FROM_PLUGIN_TO("acl_plugin.so", s, s)
 
 static inline clib_error_t * acl_plugin_exports_init (void)
 {
+    LOAD_SYMBOL_FROM_PLUGIN_TO("acl_plugin.so", acl_main, p_acl_main);
     LOAD_SYMBOL(acl_plugin_acl_exists);
     LOAD_SYMBOL(acl_plugin_register_user_module);
     LOAD_SYMBOL(acl_plugin_get_lookup_context_index);
@@ -345,7 +359,7 @@ always_inline void
 acl_plugin_fill_5tuple_inline (u32 lc_index, vlib_buffer_t * b0, int is_ip6,
 		 int is_input, int is_l2_path, fa_5tuple_opaque_t * p5tuple_pkt)
 {
-  acl_main_t *am = &acl_main;
+  acl_main_t *am = p_acl_main;
   acl_fill_5tuple(am, b0, is_ip6, is_input, is_l2_path, (fa_5tuple_t *)p5tuple_pkt);
 }
 
@@ -528,7 +542,7 @@ acl_plugin_single_acl_match_5tuple (u32 acl_index, fa_5tuple_t * pkt_5tuple,
 		  int is_ip6, u8 * r_action, u32 * r_acl_match_p,
 		  u32 * r_rule_match_p, u32 * trace_bitmap)
 {
-  acl_main_t * am = &acl_main;
+  acl_main_t * am = p_acl_main;
   return single_acl_match_5tuple(am, acl_index, pkt_5tuple, is_ip6, r_action,
                                  r_acl_match_p, r_rule_match_p, trace_bitmap);
 }
@@ -538,7 +552,7 @@ linear_multi_acl_match_5tuple (u32 lc_index, fa_5tuple_t * pkt_5tuple,
 		       int is_ip6, u8 *r_action, u32 *acl_pos_p, u32 * acl_match_p,
 		       u32 * rule_match_p, u32 * trace_bitmap)
 {
-  acl_main_t *am = &acl_main;
+  acl_main_t *am = p_acl_main;
   int i;
   u32 *acl_vector;
   u8 action = 0;
@@ -691,7 +705,7 @@ hash_multi_acl_match_5tuple (u32 lc_index, fa_5tuple_t * pkt_5tuple,
                        int is_ip6, u8 *action, u32 *acl_pos_p, u32 * acl_match_p,
                        u32 * rule_match_p, u32 * trace_bitmap)
 {
-  acl_main_t *am = &acl_main;
+  acl_main_t *am = p_acl_main;
   applied_hash_ace_entry_t **applied_hash_aces = vec_elt_at_index(am->hash_entry_vec_by_lc_index, lc_index);
   u32 match_index = multi_acl_match_get_applied_ace_index(am, pkt_5tuple);
   if (match_index < vec_len((*applied_hash_aces))) {
@@ -717,7 +731,7 @@ acl_plugin_match_5tuple_inline (u32 lc_index,
                                            u32 * r_rule_match_p,
                                            u32 * trace_bitmap)
 {
-  acl_main_t *am = &acl_main;
+  acl_main_t *am = p_acl_main;
   if (am->use_hash_acl_matching) {
     return hash_multi_acl_match_5tuple(lc_index, (fa_5tuple_t *)pkt_5tuple, is_ip6, r_action,
                                  r_acl_pos_p, r_acl_match_p, r_rule_match_p, trace_bitmap);