1 files changed, 101 insertions, 0 deletions
diff --git a/src/lib/protocols/bacnet.c b/src/lib/protocols/bacnet.c
new file mode 100644
index 000000000..907320e4f
--- /dev/null
+++ b/src/lib/protocols/bacnet.c
@@ -0,0 +1,101 @@
+/*
+ * bacnet.c
+ *
+ * Building Automation and Control Network
+ *
+ * Copyright (C) 2023 - ntop.org
+ *
+ * nDPI is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * nDPI is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with nDPI.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+
+#include "ndpi_protocol_ids.h"
+
+#define NDPI_CURRENT_PROTO NDPI_PROTOCOL_BACNET
+
+#include "ndpi_api.h"
+
+// BVLC (BACnet Virtual Link Control) Annex is part of BVLL (BACnet Virtual Link Layer).
+// See: https://www.ashrae.org/file%20library/technical%20resources/standards%20and%20guidelines/standards%20addenda/135-1995_addendum-a.pdf
+PACK_ON
+struct bvlc_header {
+  uint8_t type;
+  uint8_t function;
+  uint16_t length;
+} PACK_OFF;
+
+static void ndpi_int_bacnet_add_connection(struct ndpi_detection_module_struct * const ndpi_struct,
+                                           struct ndpi_flow_struct * const flow)
+{
+  NDPI_LOG_INFO(ndpi_struct, "found BACnet\n");
+
+  ndpi_set_detected_protocol(ndpi_struct, flow,
+                             NDPI_PROTOCOL_BACNET,
+                             NDPI_PROTOCOL_UNKNOWN,
+                             NDPI_CONFIDENCE_DPI);
+}
+
+/* ***************************************************** */
+
+static void ndpi_search_bacnet(struct ndpi_detection_module_struct *ndpi_struct,
+                               struct ndpi_flow_struct *flow)
+{
+  struct ndpi_packet_struct const * const packet = &ndpi_struct->packet;
+  struct bvlc_header const * const bvlc = (struct bvlc_header *)&packet->payload[0];
+
+  NDPI_LOG_DBG(ndpi_struct, "search BACnet\n");
+
+  if (packet->payload_packet_len < sizeof(*bvlc))
+  {
+    NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
+    return;
+  }
+
+  if (bvlc->type != 0x81)
+  {
+    NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
+    return;
+  }
+
+  if (bvlc->function > 0x0b)
+  {
+    NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
+    return;
+  }
+
+  if (ntohs(bvlc->length) != packet->payload_packet_len)
+  {
+    NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
+    return;
+  }
+
+  ndpi_int_bacnet_add_connection(ndpi_struct, flow);
+}
+
+/* ***************************************************** */
+  
+void init_bacnet_dissector(struct ndpi_detection_module_struct *ndpi_struct,
+                           u_int32_t *id)
+{
+  ndpi_set_bitmask_protocol_detection("BACnet", ndpi_struct, *id,
+                                      NDPI_PROTOCOL_BACNET,
+                                      ndpi_search_bacnet,
+                                      NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_UDP_WITH_PAYLOAD,
+                                      SAVE_DETECTION_BITMASK_AS_UNKNOWN,
+                                      ADD_TO_DETECTION_BITMASK
+                                     );
+
+  *id += 1;
+}