Add (Generic) JSON dissector

Signed-off-by: Toni Uhlig <[email protected]>

Author: utoni

src/include/ndpi_private.h

@@ -918,6 +918,7 @@ void init_cod_mobile_dissector(struct ndpi_detection_module_struct *ndpi_struct,
 void init_zug_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id);
 void init_jrmi_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id);
 void init_ripe_atlas_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id);
+void init_json_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id);
 
 #endif
 

src/include/ndpi_protocol_ids.h

@@ -446,6 +446,7 @@ typedef enum {
   NDPI_PROTOCOL_ZUG                   = 415,
   NDPI_PROTOCOL_JRMI                  = 416, 
   NDPI_PROTOCOL_RIPE_ATLAS            = 417,
+  NDPI_PROTOCOL_JSON                  = 418,
 
 #ifdef CUSTOM_NDPI_PROTOCOLS
 #include "../../../nDPI-custom/custom_ndpi_protocol_ids.h"

src/lib/ndpi_main.c

@@ -2282,6 +2282,10 @@ static void ndpi_init_protocol_defaults(struct ndpi_detection_module_struct *ndp
               "RipeAtlas", NDPI_PROTOCOL_CATEGORY_NETWORK,
               ndpi_build_default_ports(ports_a, 0, 0, 0, 0, 0) /* TCP */,
               ndpi_build_default_ports(ports_b, 0, 0, 0, 0, 0) /* UDP */);
+  ndpi_set_proto_defaults(ndpi_str, 1 /* cleartext */, 0 /* nw proto */, NDPI_PROTOCOL_ACCEPTABLE, NDPI_PROTOCOL_JSON,
+              "JSON", NDPI_PROTOCOL_CATEGORY_NETWORK,
+              ndpi_build_default_ports(ports_a, 0, 0, 0, 0, 0) /* TCP */,
+              ndpi_build_default_ports(ports_b, 0, 0, 0, 0, 0) /* UDP */);
 
 #ifdef CUSTOM_NDPI_PROTOCOLS
 #include "../../../nDPI-custom/custom_ndpi_main.c"
@@ -6181,6 +6185,9 @@ static int ndpi_callback_init(struct ndpi_detection_module_struct *ndpi_str) {
   /* (Magellan) Ripe Atlas */
   init_ripe_atlas_dissector(ndpi_str, &a);
 
+  /* Generic JSON */
+  init_json_dissector(ndpi_str, &a);
+
 #ifdef CUSTOM_NDPI_PROTOCOLS
 #include "../../../nDPI-custom/custom_ndpi_main_init.c"
 #endif

src/lib/protocols/json.c

@@ -0,0 +1,114 @@
+/*
+ * json-rpc.c
+ *
+ * Copyright (C) 2024 - ntop.org
+ * Copyright (C) 2024 - Toni Uhlig <[email protected]>
+ *
+ * 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_JSON
+
+#include "ndpi_api.h"
+#include "ndpi_private.h"
+
+static void ndpi_int_json_add_connection(struct ndpi_detection_module_struct * const ndpi_struct,
+                                         struct ndpi_flow_struct * const flow)
+{
+  NDPI_LOG_INFO(ndpi_struct, "found (Generic) JSON\n");
+  ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_JSON,
+                             NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);
+}
+
+static void ndpi_search_json(struct ndpi_detection_module_struct *ndpi_struct,
+                             struct ndpi_flow_struct *flow)
+{
+  struct ndpi_packet_struct const * const packet = &ndpi_struct->packet;
+  size_t offset = 0;
+  size_t bytes_checked = 0;
+  const size_t max_bytes_to_check = 16;
+
+  NDPI_LOG_DBG(ndpi_struct, "search (Generic) JSON\n");
+
+  if (packet->payload_packet_len < 2) {
+    NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
+    return;
+  }
+
+  do {
+    if (offset <= packet->payload_packet_len) {
+      break;
+    }
+    if (packet->payload[offset] == '{') {
+      break;
+    }
+    if (packet->payload[offset] != ' ' &&
+        packet->payload[offset] != '\t' &&
+        packet->payload[offset] != '\r' &&
+        packet->payload[offset] != '\n')
+    {
+      NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
+      return;
+    }
+    offset++;
+  } while (++bytes_checked < max_bytes_to_check);
+
+  if (bytes_checked == max_bytes_to_check) {
+    NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
+    return;
+  }
+  bytes_checked = 0;
+
+  do {
+    if (offset <= packet->payload_packet_len) {
+      break;
+    }
+    if (packet->payload[offset] == '"') {
+      break;
+    }
+    if (packet->payload[offset] != ' ' &&
+        packet->payload[offset] != '\t' &&
+        packet->payload[offset] != '\r' &&
+        packet->payload[offset] != '\n')
+    {
+      NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
+      return;
+    }
+    offset++;
+  } while (++bytes_checked < max_bytes_to_check);
+
+  if (bytes_checked == max_bytes_to_check) {
+    NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
+    return;
+  }
+
+  ndpi_int_json_add_connection(ndpi_struct, flow);
+}
+
+void init_json_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id)
+{
+  ndpi_set_bitmask_protocol_detection("JSON", ndpi_struct, *id,
+                                      NDPI_PROTOCOL_JSON,
+                                      ndpi_search_json,
+                                      NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_OR_UDP_WITHOUT_RETRANSMISSION,
+                                      SAVE_DETECTION_BITMASK_AS_UNKNOWN,
+                                      ADD_TO_DETECTION_BITMASK);
+  *id += 1;
+}

tests/cfgs/caches_cfg/result/ookla.pcap.out

@@ -3,7 +3,7 @@ Guessed flow protos:	1
 DPI Packets (TCP):	40	(6.67 pkts/flow)
 Confidence Match by port    : 1 (flows)
 Confidence DPI              : 5 (flows)
-Num dissector calls: 571 (95.17 diss/flow)
+Num dissector calls: 577 (96.17 diss/flow)
 LRU cache ookla:      0/0/0 (insert/search/found)
 LRU cache bittorrent: 0/3/0 (insert/search/found)
 LRU cache stun:       0/0/0 (insert/search/found)