Add IEC62056 (DLMS/COSEM) protocol dissector (#2229)

* Add IEC62056 (DLMS/COSEM) protocol dissector

* Fix detection on big endian architectures

* Update protocols.rst

* Add ndpi_crc16_x25 to fuzz/fuzz_alg_crc32_md5.c

* Update pcap sample

* Remove empty .out file

* iec62056: add some documentation

---------

Co-authored-by: Nardi Ivan <nardi.ivan@gmail.com>

6 files changed, 93 insertions, 0 deletions

diff --git a/src/include/ndpi_api.h b/src/include/ndpi_api.h
index c7da8d8a9..7238b04b3 100644
--- a/src/include/ndpi_api.h
+++ b/src/include/ndpi_api.h
@@ -1793,6 +1793,7 @@ extern "C" {
   u_int16_t ndpi_crc16_ccit(const void* data, size_t n_bytes);
   u_int16_t ndpi_crc16_ccit_false(const void *data, size_t n_bytes);
   u_int16_t ndpi_crc16_xmodem(const void *data, size_t n_bytes);
+  u_int16_t ndpi_crc16_x25(const void* data, size_t n_bytes);
   u_int32_t ndpi_crc32(const void* data, size_t n_bytes);
   u_int32_t ndpi_nearest_power_of_two(u_int32_t x);
 
diff --git a/src/include/ndpi_protocol_ids.h b/src/include/ndpi_protocol_ids.h
index 8a1559403..954960554 100644
--- a/src/include/ndpi_protocol_ids.h
+++ b/src/include/ndpi_protocol_ids.h
@@ -407,6 +407,7 @@ typedef enum {
   NDPI_PROTOCOL_WEBDAV                = 376,
   NDPI_PROTOCOL_APACHE_KAFKA          = 377,
   NDPI_PROTOCOL_NOMACHINE             = 378,
+  NDPI_PROTOCOL_IEC62056              = 379,
 
 #ifdef CUSTOM_NDPI_PROTOCOLS
 #include "../../../nDPI-custom/custom_ndpi_protocol_ids.h"
diff --git a/src/lib/ndpi_analyze.c b/src/lib/ndpi_analyze.c
index 198aa4f9f..d1b1c38ec 100644
--- a/src/lib/ndpi_analyze.c
+++ b/src/lib/ndpi_analyze.c
@@ -1833,6 +1833,15 @@ u_int16_t ndpi_crc16_xmodem(const void *data, size_t n_bytes) {
   return __crc16(0, data, n_bytes);
 }
 
+u_int16_t ndpi_crc16_x25(const void* data, size_t n_bytes) {
+  u_int16_t crc = 0xFFFF;
+  u_int8_t* b = (u_int8_t*)data;
+  while (n_bytes--) {
+    crc = (crc >> 8) ^ crc16_ccitt_table[(crc ^ *b++) & 0xFF];
+  }
+  return (crc ^ 0xFFFF);
+}
+
 /* ********************************************************** */
 /*       http://home.thep.lu.se/~bjorn/crc/crc32_fast.c       */
 /* ********************************************************** */
diff --git a/src/lib/ndpi_main.c b/src/lib/ndpi_main.c
index aa497b685..9f32c8c8b 100644
--- a/src/lib/ndpi_main.c
+++ b/src/lib/ndpi_main.c
@@ -2222,6 +2222,10 @@ static void ndpi_init_protocol_defaults(struct ndpi_detection_module_struct *ndp
 			  "NoMachine", NDPI_PROTOCOL_CATEGORY_REMOTE_ACCESS,
 			  ndpi_build_default_ports(ports_a, 4000, 0, 0, 0, 0) /* TCP */,
 			  ndpi_build_default_ports(ports_b, 4000, 0, 0, 0, 0) /* UDP */);
+  ndpi_set_proto_defaults(ndpi_str, 1 /* cleartext */, 0 /* nw proto */, NDPI_PROTOCOL_ACCEPTABLE, NDPI_PROTOCOL_IEC62056,
+			  "IEC62056", NDPI_PROTOCOL_CATEGORY_IOT_SCADA,
+			  ndpi_build_default_ports(ports_a, 4059, 0, 0, 0, 0) /* TCP */,
+			  ndpi_build_default_ports(ports_b, 4059, 0, 0, 0, 0) /* UDP */);
 
 #ifdef CUSTOM_NDPI_PROTOCOLS
 #include "../../../nDPI-custom/custom_ndpi_main.c"
@@ -5731,6 +5735,9 @@ static int ndpi_callback_init(struct ndpi_detection_module_struct *ndpi_str) {
   /* NoMachine */
   init_nomachine_dissector(ndpi_str, &a);
 
+  /* IEC 62056 */
+  init_iec62056_dissector(ndpi_str, &a);
+
 #ifdef CUSTOM_NDPI_PROTOCOLS
 #include "../../../nDPI-custom/custom_ndpi_main_init.c"
 #endif
diff --git a/src/lib/ndpi_private.h b/src/lib/ndpi_private.h
index a14a87635..8e0705ce7 100644
--- a/src/lib/ndpi_private.h
+++ b/src/lib/ndpi_private.h
@@ -641,6 +641,7 @@ void init_openflow_dissector(struct ndpi_detection_module_struct *ndpi_struct, u
 void init_json_rpc_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id);
 void init_kafka_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id);
 void init_nomachine_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id);
+void init_iec62056_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id);
 
 #endif
 
diff --git a/src/lib/protocols/iec62056.c b/src/lib/protocols/iec62056.c
new file mode 100644
index 000000000..10542c7ba
--- /dev/null
+++ b/src/lib/protocols/iec62056.c
@@ -0,0 +1,74 @@
+/*
+ * iec62056.c
+ *
+ * IEC 62056-4-7 DLMS/COSEM transport layer for IP networks
+ * 
+ * Copyright (C) 2023 - ntop.org
+ * Copyright (C) 2023 - V.G <jacendi@protonmail.com>
+ *
+ * This file is part of nDPI, an open source deep packet inspection
+ * library based on the OpenDPI and PACE technology by ipoque GmbH
+ *
+ * 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_IEC62056
+
+#include "ndpi_api.h"
+#include "ndpi_private.h"
+
+static void ndpi_int_iec62056_add_connection(struct ndpi_detection_module_struct *ndpi_struct,
+                                             struct ndpi_flow_struct *flow)
+{
+  NDPI_LOG_INFO(ndpi_struct, "found IEC62056\n");
+  ndpi_set_detected_protocol(ndpi_struct, flow,
+                             NDPI_PROTOCOL_IEC62056, NDPI_PROTOCOL_UNKNOWN,
+                             NDPI_CONFIDENCE_DPI);
+}
+
+static void ndpi_search_iec62056(struct ndpi_detection_module_struct *ndpi_struct,
+                                 struct ndpi_flow_struct *flow)
+{
+  struct ndpi_packet_struct const * const packet = &ndpi_struct->packet;
+
+  NDPI_LOG_DBG(ndpi_struct, "search IEC62056\n");
+
+  if (packet->payload_packet_len > 8 && /* Smallest suitable packet (SNRM request) is 9 bytes long */
+      packet->payload[0] == 0x7E && packet->payload[1] == 0xA0 && /* HDLC frame start */
+      packet->payload[packet->payload_packet_len-1] == 0x7E) /* HDLC frame end */
+  {
+    u_int16_t fcs = le16toh(ndpi_crc16_x25(&packet->payload[1], packet->payload_packet_len-4));
+    if (fcs == get_u_int16_t(packet->payload, packet->payload_packet_len-3)) {
+      ndpi_int_iec62056_add_connection(ndpi_struct,  flow);
+      return;
+    }
+  }
+
+  NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
+}
+
+void init_iec62056_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id)
+{
+  ndpi_set_bitmask_protocol_detection("IEC62056", ndpi_struct, *id,
+                                      NDPI_PROTOCOL_IEC62056,
+                                      ndpi_search_iec62056,
+                                      NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_OR_UDP_WITH_PAYLOAD_WITHOUT_RETRANSMISSION,
+                                      SAVE_DETECTION_BITMASK_AS_UNKNOWN,
+                                      ADD_TO_DETECTION_BITMASK);
+
+  *id += 1;
+}