XIAOMI: add detection of Xiaomi traffic (#1529)

Most of the credits should go to @utoni (see #1521)

6 files changed, 144 insertions, 7 deletions

diff --git a/src/include/ndpi_protocol_ids.h b/src/include/ndpi_protocol_ids.h
index 082db5cd0..146fd644b 100644
--- a/src/include/ndpi_protocol_ids.h
+++ b/src/include/ndpi_protocol_ids.h
@@ -315,6 +315,7 @@ typedef enum {
   NDPI_PROTOCOL_GOOGLE_CLOUD          = 284,
   NDPI_PROTOCOL_TENCENT               = 285,
   NDPI_PROTOCOL_RAKNET                = 286,
+  NDPI_PROTOCOL_XIAOMI                = 287,
 
 #ifdef CUSTOM_NDPI_PROTOCOLS
 #include "../../../nDPI-custom/custom_ndpi_protocol_ids.h"
diff --git a/src/include/ndpi_protocols.h b/src/include/ndpi_protocols.h
index ea83f13ec..0f0103e49 100644
--- a/src/include/ndpi_protocols.h
+++ b/src/include/ndpi_protocols.h
@@ -224,6 +224,7 @@ void init_ethernet_ip_dissector(struct ndpi_detection_module_struct *ndpi_struct
 void init_toca_boca_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id, NDPI_PROTOCOL_BITMASK *detection_bitmask);
 void init_sd_rtn_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id, NDPI_PROTOCOL_BITMASK *detection_bitmask);
 void init_raknet_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id, NDPI_PROTOCOL_BITMASK *detection_bitmask);
+void init_xiaomi_dissector(struct ndpi_detection_module_struct *ndpi_struct, u_int32_t *id, NDPI_PROTOCOL_BITMASK *detection_bitmask);
 
 /* ndpi_main.c */
 extern u_int32_t ndpi_ip_port_hash_funct(u_int32_t ip, u_int16_t port);
diff --git a/src/include/ndpi_typedefs.h b/src/include/ndpi_typedefs.h
index b3036ffc1..109b3a0cc 100644
--- a/src/include/ndpi_typedefs.h
+++ b/src/include/ndpi_typedefs.h
@@ -1186,7 +1186,7 @@ struct ndpi_flow_struct {
 
   /* General purpose field used to save mainly hostname/SNI information.
    * In details it used for: DNS and NETBIOS name, HTTP and DHCP hostname,
-   * WHOIS request, TLS/QUIC server name and STUN realm.
+   * WHOIS request, TLS/QUIC server name, XIAOMI domain and STUN realm.
    *
    * Please, think *very* hard before increasing its size!
    */
diff --git a/src/lib/ndpi_content_match.c.inc b/src/lib/ndpi_content_match.c.inc
index a2bd9a0d9..3371c1aa8 100644
--- a/src/lib/ndpi_content_match.c.inc
+++ b/src/lib/ndpi_content_match.c.inc
@@ -1604,6 +1604,11 @@ static ndpi_protocol_match host_match[] =
    { "zn6qzq6caaucudesr-pluralsight.siteintercept.qualtrics.com",           "Pluralsight", NDPI_PROTOCOL_PLURALSIGHT, NDPI_PROTOCOL_CATEGORY_STREAMING, NDPI_PROTOCOL_FUN, NDPI_PROTOCOL_DEFAULT_LEVEL },
    { "ip-video-course-exercise-files-us-west-2.s3.us-west-2.amazonaws.com", "Pluralsight", NDPI_PROTOCOL_PLURALSIGHT, NDPI_PROTOCOL_CATEGORY_STREAMING, NDPI_PROTOCOL_FUN, NDPI_PROTOCOL_DEFAULT_LEVEL },
 
+   { "xiaomi.com",                       "Xiaomi", NDPI_PROTOCOL_XIAOMI, NDPI_PROTOCOL_CATEGORY_WEB, NDPI_PROTOCOL_SAFE, NDPI_PROTOCOL_DEFAULT_LEVEL },
+   { "xiaomi.net",                       "Xiaomi", NDPI_PROTOCOL_XIAOMI, NDPI_PROTOCOL_CATEGORY_WEB, NDPI_PROTOCOL_SAFE, NDPI_PROTOCOL_DEFAULT_LEVEL },
+   { "mi.com",                           "Xiaomi", NDPI_PROTOCOL_XIAOMI, NDPI_PROTOCOL_CATEGORY_WEB, NDPI_PROTOCOL_SAFE, NDPI_PROTOCOL_DEFAULT_LEVEL },
+   { "miui.com",                         "Xiaomi", NDPI_PROTOCOL_XIAOMI, NDPI_PROTOCOL_CATEGORY_WEB, NDPI_PROTOCOL_SAFE, NDPI_PROTOCOL_DEFAULT_LEVEL },
+
 #ifdef CUSTOM_NDPI_PROTOCOLS
 #include "../../../nDPI-custom/custom_ndpi_content_match_host_match.c.inc"
 #endif
diff --git a/src/lib/ndpi_main.c b/src/lib/ndpi_main.c
index 9432ce64b..5a6376c6f 100644
--- a/src/lib/ndpi_main.c
+++ b/src/lib/ndpi_main.c
@@ -1859,13 +1859,17 @@ static void ndpi_init_protocol_defaults(struct ndpi_detection_module_struct *ndp
                           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 */, NDPI_PROTOCOL_ACCEPTABLE, NDPI_PROTOCOL_TENCENT,
-			  "Tencent", NDPI_PROTOCOL_CATEGORY_SOCIAL_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 */);
+                          "Tencent", NDPI_PROTOCOL_CATEGORY_SOCIAL_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 */, NDPI_PROTOCOL_ACCEPTABLE, NDPI_PROTOCOL_RAKNET,
-              "RakNet", NDPI_PROTOCOL_CATEGORY_GAME,
-              ndpi_build_default_ports(ports_a, 0, 0, 0, 0, 0), /* TCP */
-              ndpi_build_default_ports(ports_b, 0, 0, 0, 0, 0) /* UDP */);
+                          "RakNet", NDPI_PROTOCOL_CATEGORY_GAME,
+                          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, 0 /* encrypted */, NDPI_PROTOCOL_ACCEPTABLE, NDPI_PROTOCOL_XIAOMI,
+                          "Xiaomi", NDPI_PROTOCOL_CATEGORY_WEB,
+                          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"
@@ -4345,6 +4349,9 @@ static int ndpi_callback_init(struct ndpi_detection_module_struct *ndpi_str) {
   /* RakNet */
   init_raknet_dissector(ndpi_str, &a, detection_bitmask);
 
+  /* Xiaomi */
+  init_xiaomi_dissector(ndpi_str, &a, detection_bitmask);
+
 #ifdef CUSTOM_NDPI_PROTOCOLS
 #include "../../../nDPI-custom/custom_ndpi_main_init.c"
 #endif
diff --git a/src/lib/protocols/xiaomi.c b/src/lib/protocols/xiaomi.c
new file mode 100644
index 000000000..831478e9e
--- /dev/null
+++ b/src/lib/protocols/xiaomi.c
@@ -0,0 +1,123 @@
+/*
+ * xiaomi.c
+ *
+ * Copyright (C) 2022 - ntop.org
+ *
+ * nDPI is free software: you can zmqtribute 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_XIAOMI
+
+#include "ndpi_api.h"
+
+
+static void xiaomi_dissect_metadata(struct ndpi_detection_module_struct *ndpi_struct,
+                                    struct ndpi_flow_struct * const flow,
+                                    u_int8_t const * const payload,
+                                    u_int32_t payload_len)
+{
+  size_t offset = 16;
+
+  while(offset + 1 < payload_len) {
+    char *ptr;
+    u_int8_t op = payload[offset];
+    u_int8_t len = payload[offset + 1];
+
+    offset += 2;
+
+    /* "Strage" types which don't respect the TLV format */
+    if(op == 0x28 || op == 0x08) {
+      continue;
+    }
+
+    if(offset + len >= payload_len) {
+      break;
+    }
+
+    NDPI_LOG_DBG(ndpi_struct, "TLV: 0x%x len %d [%.*s]\n",
+                 op, len, len, &payload[offset]);
+
+    switch(op) {
+      case 0x12:
+        flow->http.user_agent = ndpi_malloc(len + 1);
+        if(flow->http.user_agent != NULL) {
+          memcpy(flow->http.user_agent, &payload[offset], len);
+          flow->http.user_agent[len] = '\0';
+        }
+        break;
+
+      case 0x3a:
+        /* If "domain:port", strip the port */
+        ptr = ndpi_strnstr((const char *)&payload[offset], ":", len);
+        if(ptr == NULL)
+          ndpi_hostname_sni_set(flow, &payload[offset], len);
+        else
+          ndpi_hostname_sni_set(flow, &payload[offset], (const u_int8_t *)ptr - &payload[offset]);
+        break;
+
+      case 0x32: /* Radio access technology (+ APN) */
+      case 0x1A: /* Build version */
+      case 0x42: /* Locale */
+      default:
+        break;
+    }
+    offset += len;
+  }
+}
+
+static void ndpi_search_xiaomi(struct ndpi_detection_module_struct *ndpi_struct,
+			       struct ndpi_flow_struct *flow)
+{
+  struct ndpi_packet_struct *packet = &ndpi_struct->packet;
+
+  NDPI_LOG_DBG(ndpi_struct, "search Xiaomi\n");
+
+  if(packet->payload_packet_len >= 12) {
+    uint32_t len;
+
+    len = ntohl(get_u_int32_t(packet->payload, 4));
+    if(len + 12 == packet->payload_packet_len &&
+       ntohl(get_u_int32_t(packet->payload, 0)) == 0xC2FE0005 &&
+       ntohl(get_u_int32_t(packet->payload, 8)) == 0x00020016) {
+      NDPI_LOG_INFO(ndpi_struct, "found Xiaomi\n");
+      ndpi_set_detected_protocol(ndpi_struct, flow, NDPI_PROTOCOL_XIAOMI, NDPI_PROTOCOL_UNKNOWN, NDPI_CONFIDENCE_DPI);
+
+      /* Better way to detect "client" packets? */
+      if(ntohs(packet->tcp->dest) == 5222) {
+        /* It seems that the "TLV list" is different for client and for server messages.
+           For example, the type 0x12 is used as user-agent by the client and
+           as something else by the server. We are interested in the metadata sent by the client */
+        xiaomi_dissect_metadata(ndpi_struct, flow, packet->payload, packet->payload_packet_len);
+      }
+
+      return;
+    }
+  }
+
+  NDPI_EXCLUDE_PROTO(ndpi_struct, flow);
+}
+
+void init_xiaomi_dissector(struct ndpi_detection_module_struct *ndpi_struct,
+			   u_int32_t *id,
+			   NDPI_PROTOCOL_BITMASK *detection_bitmask) {
+  ndpi_set_bitmask_protocol_detection("Xiaomi", ndpi_struct, detection_bitmask, *id,
+				      NDPI_PROTOCOL_XIAOMI,
+				      ndpi_search_xiaomi,
+				      NDPI_SELECTION_BITMASK_PROTOCOL_V4_V6_TCP_WITH_PAYLOAD_WITHOUT_RETRANSMISSION,
+				      SAVE_DETECTION_BITMASK_AS_UNKNOWN,
+				      ADD_TO_DETECTION_BITMASK);
+  *id += 1;
+}