ndpi: use SigMatch accessors for keyword conflict checks

Walk earlier ndpi-protocol and ndpi-risk instances with
SCDetectSignatureGetLastSMByType, SCSigMatchGetPrevByType and
SCSigMatchGetCtx instead of reading the signature's match list and
SigMatch fields directly. The list is now walked newest first, which
makes no difference to the conflict checks.

No Signature or SigMatch internals are accessed by the plugin anymore.

Related to ticket: 7499

plugins/ndpi/ndpi.c

@@ -320,16 +320,15 @@ static int DetectnDPIProtocolSetup(DetectEngineCtx *de_ctx, Signature *s, const
     if (data == NULL)
         goto error;
 
-    SigMatch *tsm = s->init_data->smlists[DETECT_SM_LIST_MATCH];
-    for (; tsm != NULL; tsm = tsm->next) {
-        if (tsm->type == ndpi_protocol_keyword_id) {
-            const DetectnDPIProtocolData *them = (const DetectnDPIProtocolData *)tsm->ctx;
-
-            if (nDPIProtocolDataHasConflicts(data, them)) {
-                SCLogError("can't mix "
-                           "positive ndpi-protocol match with negated");
-                goto error;
-            }
+    const SigMatch *tsm =
+            SCDetectSignatureGetLastSMByType(s, DETECT_SM_LIST_MATCH, ndpi_protocol_keyword_id);
+    for (; tsm != NULL; tsm = SCSigMatchGetPrevByType(tsm, ndpi_protocol_keyword_id)) {
+        const DetectnDPIProtocolData *them = (const DetectnDPIProtocolData *)SCSigMatchGetCtx(tsm);
+
+        if (nDPIProtocolDataHasConflicts(data, them)) {
+            SCLogError("can't mix "
+                       "positive ndpi-protocol match with negated");
+            goto error;
         }
     }
 
@@ -460,16 +459,15 @@ static int DetectnDPIRiskSetup(DetectEngineCtx *de_ctx, Signature *s, const char
     if (data == NULL)
         goto error;
 
-    SigMatch *tsm = s->init_data->smlists[DETECT_SM_LIST_MATCH];
-    for (; tsm != NULL; tsm = tsm->next) {
-        if (tsm->type == ndpi_risk_keyword_id) {
-            const DetectnDPIRiskData *them = (const DetectnDPIRiskData *)tsm->ctx;
+    const SigMatch *tsm =
+            SCDetectSignatureGetLastSMByType(s, DETECT_SM_LIST_MATCH, ndpi_risk_keyword_id);
+    for (; tsm != NULL; tsm = SCSigMatchGetPrevByType(tsm, ndpi_risk_keyword_id)) {
+        const DetectnDPIRiskData *them = (const DetectnDPIRiskData *)SCSigMatchGetCtx(tsm);
 
-            if (nDPIRiskDataHasConflicts(data, them)) {
-                SCLogError("can't mix "
-                           "positive ndpi-risk match with negated");
-                goto error;
-            }
+        if (nDPIRiskDataHasConflicts(data, them)) {
+            SCLogError("can't mix "
+                       "positive ndpi-risk match with negated");
+            goto error;
         }
     }