Use COUNT_OF macro for message_handlers bounds check

Summary: Currently we calculate the size of a 2d array with messy sizeof calculations. In this diff, we pull in a macro from chromium (sourced from SO) to make this calculation simpler and semantically more clear. Reviewed By: vikg-fb Differential Revision: D14690805 fbshipit-source-id: c106198a8ddc902e3cfc7fe85364e462eb716e30
magma · Apr 3, 2019 · 861a7b3 · 861a7b3
1 parent 5bdee78
commit 861a7b3
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Showing 2 changed files with 5 additions and 3 deletions.
diff --git a/lte/gateway/c/oai/common/common_defs.h b/lte/gateway/c/oai/common/common_defs.h
@@ -43,6 +43,9 @@
 #define CLONE_REF
 
 #define OFFSET_OF(TyPe, MeMBeR) ((size_t) & ((TyPe *) 0)->MeMBeR)
+// https://stackoverflow.com/questions/4415524/common-array-length-macro-for-c
+#define COUNT_OF(x)                                                            \
+  ((sizeof(x) / sizeof(0 [x])) / ((size_t)(!(sizeof(x) % sizeof(0 [x])))))
 
 #define PARENT_STRUCT(cOnTaiNeD, TyPe, MeMBeR)                                 \
   ({                                                                           \

diff --git a/lte/gateway/c/oai/tasks/s1ap/s1ap_mme_handlers.c b/lte/gateway/c/oai/tasks/s1ap/s1ap_mme_handlers.c
@@ -195,9 +195,8 @@ int s1ap_mme_handle_message(
    * Checking procedure Code and direction of message
    */
   if (
-    (message->procedureCode >
-     (sizeof(message_handlers) / (3 * sizeof(s1ap_message_handler_t)))) ||
-    (message->direction > S1AP_PDU_PR_unsuccessfulOutcome)) {
+    message->procedureCode >= COUNT_OF(message_handlers) ||
+    message->direction > S1AP_PDU_PR_unsuccessfulOutcome) {
     OAILOG_DEBUG(
       LOG_S1AP,
       "[SCTP %d] Either procedureCode %d or direction %d exceed expected\n",