detect: support http.protocol for HTTP2

Ticket: #4067

By having a synthetic constant HTTP/2 buffer

src/detect-http-protocol.c

@@ -75,7 +75,7 @@ static int DetectHttpProtocolSetup(DetectEngineCtx *de_ctx, Signature *s, const
     if (DetectBufferSetActiveList(de_ctx, s, g_buffer_id) < 0)
         return -1;
 
-    if (DetectSignatureSetAppProto(s, ALPROTO_HTTP1) < 0)
+    if (DetectSignatureSetAppProto(s, ALPROTO_HTTP) < 0)
         return -1;
 
     return 0;
@@ -114,6 +114,20 @@ static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
     return buffer;
 }
 
+static InspectionBuffer *GetData2(DetectEngineThreadCtx *det_ctx,
+        const DetectEngineTransforms *transforms, Flow *_f, const uint8_t _flow_flags, void *txv,
+        const int list_id)
+{
+    InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
+    if (buffer->inspect == NULL) {
+        InspectionBufferSetup(
+                det_ctx, list_id, buffer, (const uint8_t *)"HTTP/2", strlen("HTTP/2"));
+        InspectionBufferApplyTransforms(buffer, transforms);
+    }
+
+    return buffer;
+}
+
 /**
  * \brief Registers the keyword handlers for the "http.protocol" keyword.
  */
@@ -135,6 +149,15 @@ void DetectHttpProtocolRegister(void)
     DetectAppLayerInspectEngineRegister2(BUFFER_NAME, ALPROTO_HTTP1, SIG_FLAG_TOCLIENT,
             HTP_RESPONSE_LINE, DetectEngineInspectBufferGeneric, GetData);
 
+    DetectAppLayerInspectEngineRegister2(BUFFER_NAME, ALPROTO_HTTP2, SIG_FLAG_TOSERVER,
+            HTTP2StateDataClient, DetectEngineInspectBufferGeneric, GetData2);
+    DetectAppLayerMpmRegister2(BUFFER_NAME, SIG_FLAG_TOSERVER, 2, PrefilterGenericMpmRegister,
+            GetData2, ALPROTO_HTTP2, HTTP2StateDataClient);
+    DetectAppLayerInspectEngineRegister2(BUFFER_NAME, ALPROTO_HTTP2, SIG_FLAG_TOCLIENT,
+            HTTP2StateDataServer, DetectEngineInspectBufferGeneric, GetData2);
+    DetectAppLayerMpmRegister2(BUFFER_NAME, SIG_FLAG_TOCLIENT, 2, PrefilterGenericMpmRegister,
+            GetData2, ALPROTO_HTTP2, HTTP2StateDataServer);
+
     DetectBufferTypeSetDescriptionByName(BUFFER_NAME,
             BUFFER_DESC);