Implement Message Queue Limit to Prevent Memory Exhaustion in Embedde…

…d Devices The current network thread can produce unlimited messages to the queue which is consumed by the event thread. In embedded devices, we have limited memory, so a DDOS attack could exhaust the memory. Fixes Issue: #626 To fix this issue, (when OC_DYNAMIC_ALLOCATION is enabled) we use the macro OC_MAX_NUM_CONCURRENT_REQUESTS , which defines the maximum number of messages in the queue per device. The default value of OC_MAX_NUM_CONCURRENT_REQUESTS is 32. If the number of messages reaches the limit, all file descriptors in the network thread that produce oc_message_t are removed from select/poll. The file descriptor for monitoring the control flow is always set and is used to wake up from select() when the queue is ready to accept events again. When more file descriptors are ready to be read than the number of available queue slots, a subset is randomly selected to be pushed to the queue. --------- Co-authored-by: sp-milos <[email protected]> Co-authored-by: Daniel Adam <[email protected]>
iotivity · Jun 20, 2024 · 4a9fad5 · 4a9fad5
1 parent 09b9743
commit 4a9fad5
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diff --git a/.github/workflows/cmake-windows.yml b/.github/workflows/cmake-windows.yml
@@ -37,6 +37,12 @@ jobs:
             cc: "gcc"
             cxx: "g++"
             build_testing: "ON"
+          - name: "MinGW-gcc debug-discovery-resource-observable-rep-realloc-concurrent-requests-1"
+            build_type: "Debug"
+            cc: "gcc"
+            cxx: "g++"
+            build_testing: "ON"
+            build_args: "-DOC_DISCOVERY_RESOURCE_OBSERVABLE_ENABLED=ON -DOC_REPRESENTATION_REALLOC_ENCODING_ENABLED=ON -DOC_DEVICE_MAX_NUM_CONCURRENT_REQUESTS=1"
 
     steps:
       - name: Checkout repository
@@ -93,6 +99,7 @@ jobs:
               -D PLGD_DEV_TIME_ENABLED=ON
               -D OC_ETAG_ENABLED=ON
               -D OC_DEBUG_ENABLED=ON
+              ${{ matrix.build_args }}
             COMMAND_ERROR_IS_FATAL ANY
           )
 

diff --git a/.github/workflows/plgd-device-tests.yml b/.github/workflows/plgd-device-tests.yml
@@ -64,6 +64,14 @@ jobs:
             args: "-DOC_TSAN_ENABLED=ON -DOC_RESOURCE_ACCESS_IN_RFOTM_ENABLED=ON"
             docker_file: docker/apps/Dockerfile.cloud-server-debug-clang
 
+          - name: cloud-server-access-in-RFOTM-concurrent-requests-1
+            # same configuration as " cloud-server-access-in-RFOTM-concurrent-requests-1" in the SonarCloud scan job, skip for events that trigger both jobs
+            skip: ${{ github.event_name != 'workflow_dispatch' }}
+            args: "-DOC_RESOURCE_ACCESS_IN_RFOTM_ENABLED=ON -DOC_DEVICE_MAX_NUM_CONCURRENT_REQUESTS=1"
+          - name: cloud-server-access-in-RFOTM-concurrent-requests-1-tsan
+            args: "-DOC_TSAN_ENABLED=ON -DOC_RESOURCE_ACCESS_IN_RFOTM_ENABLED=ON -DOC_DEVICE_MAX_NUM_CONCURRENT_REQUESTS=1"
+            docker_file: docker/apps/Dockerfile.cloud-server-debug-clang
+
           - name: cloud-server-discovery-resource-observable
             args: "-DOC_DISCOVERY_RESOURCE_OBSERVABLE_ENABLED=ON"
           - name: cloud-server-discovery-resource-observable-asan

diff --git a/.github/workflows/plgd-hub-tests.yml b/.github/workflows/plgd-hub-tests.yml
@@ -137,6 +137,14 @@ jobs:
             build_args: "-DOC_DISCOVERY_RESOURCE_OBSERVABLE_ENABLED=ON -DOC_RESOURCE_ACCESS_IN_RFOTM_ENABLED=ON -DOC_REPRESENTATION_REALLOC_ENCODING_ENABLED=ON -DOC_TSAN_ENABLED=ON"
             docker_file: docker/apps/Dockerfile.cloud-server-debug-clang
 
+          - name: cloud-server-discovery-resource-observable-access-in-RFOTM-rep-realloc-concurrent-requests-1
+            # same configuration as "cloud-server-discovery-resource-observable-access-in-RFOTM-rep-realloc-concurrent-requests-1" in the SonarCloud scan job, skip for events that trigger both jobs
+            skip: ${{ github.event_name != 'workflow_dispatch' }}
+            build_args: "-DOC_DISCOVERY_RESOURCE_OBSERVABLE_ENABLED=ON -DOC_RESOURCE_ACCESS_IN_RFOTM_ENABLED=ON -DOC_REPRESENTATION_REALLOC_ENCODING_ENABLED=ON -DOC_DEVICE_MAX_NUM_CONCURRENT_REQUESTS=1"
+          - name: cloud-server-discovery-resource-observable-access-in-RFOTM-rep-realloc-concurrent-requests-1-tsan
+            build_args: "-DOC_DISCOVERY_RESOURCE_OBSERVABLE_ENABLED=ON -DOC_RESOURCE_ACCESS_IN_RFOTM_ENABLED=ON -DOC_REPRESENTATION_REALLOC_ENCODING_ENABLED=ON -DOC_DEVICE_MAX_NUM_CONCURRENT_REQUESTS=1 -DOC_TSAN_ENABLED=ON"
+            docker_file: docker/apps/Dockerfile.cloud-server-debug-clang
+
           # ports
           - name: cloud-server-tcp-disabled
             args: "--udp-port 61234 --udp-port4 61234 --dtls-port 61235 --dtls-port4 61235 --tcp-port -1 --tcp-port4 -1 --tls-port -1 --tls-port4 -1"

diff --git a/.github/workflows/sonar-cloud-analysis.yml b/.github/workflows/sonar-cloud-analysis.yml
@@ -27,8 +27,8 @@ jobs:
         include:
           # cloud (ipv4+tcp) on, collection create on, push on, rfotm on
           - build_args: "-DOC_CLOUD_ENABLED=ON -DOC_COLLECTIONS_IF_CREATE_ENABLED=ON -DOC_PUSH_ENABLED=ON -DOC_RESOURCE_ACCESS_IN_RFOTM_ENABLED=ON"
-          # security off, ipv4 on, collection create on, push on
-          - build_args: "-DOC_SECURITY_ENABLED=OFF -DOC_IPV4_ENABLED=ON -DOC_COLLECTIONS_IF_CREATE_ENABLED=ON -DOC_PUSH_ENABLED=ON"
+          # security off, ipv4 on, collection create on, push on, max num concurrent requests=1
+          - build_args: "-DOC_SECURITY_ENABLED=OFF -DOC_IPV4_ENABLED=ON -DOC_COLLECTIONS_IF_CREATE_ENABLED=ON -DOC_PUSH_ENABLED=ON -DOC_DEVICE_MAX_NUM_CONCURRENT_REQUESTS=1"
           # ipv6 dns on, oscore off, rep realloc on, json encoder on, introspection IDD off
           - build_args: "-DOC_DNS_LOOKUP_IPV6_ENABLED=ON -DOC_OSCORE_ENABLED=OFF -DOC_REPRESENTATION_REALLOC_ENCODING_ENABLED=ON -DOC_JSON_ENCODER_ENABLED=ON -DOC_IDD_API_ENABLED=OFF"
           # cloud (ipv4+tcp) on, dynamic allocation off, rfotm on, push off (because it forces dynamic allocation)
@@ -51,6 +51,8 @@ jobs:
         include:
           - name: cloud-server
             build_args: ""
+          - name: cloud-server-access-in-RFOTM-concurrent-requests-1
+            build_args: "-DOC_RESOURCE_ACCESS_IN_RFOTM_ENABLED=ON -DOC_DEVICE_MAX_NUM_CONCURRENT_REQUESTS=1"
           - name: cloud-server-discovery-resource-observable-access-in-RFOTM-rep-realloc
             build_args: "-DOC_DISCOVERY_RESOURCE_OBSERVABLE_ENABLED=ON -DOC_RESOURCE_ACCESS_IN_RFOTM_ENABLED=ON -DOC_REPRESENTATION_REALLOC_ENCODING_ENABLED=ON"
             # try with SHA384
@@ -72,6 +74,8 @@ jobs:
         include:
           - name: cloud-server-discovery-resource-observable-access-in-RFOTM
             build_args: "-DOC_DISCOVERY_RESOURCE_OBSERVABLE_ENABLED=ON -DOC_RESOURCE_ACCESS_IN_RFOTM_ENABLED=ON"
+          - name: cloud-server-discovery-resource-observable-access-in-RFOTM-rep-realloc-concurrent-requests-1
+            build_args: "-DOC_DISCOVERY_RESOURCE_OBSERVABLE_ENABLED=ON -DOC_RESOURCE_ACCESS_IN_RFOTM_ENABLED=ON -DOC_REPRESENTATION_REALLOC_ENCODING_ENABLED=ON -DOC_DEVICE_MAX_NUM_CONCURRENT_REQUESTS=1"
           - name: dtls-cloud-server-rep-realloc
             build_args: "-DOC_REPRESENTATION_REALLOC_ENCODING_ENABLED=ON"
             hub_args: "-e COAP_GATEWAY_UDP_ENABLED=true"

diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -19,6 +19,8 @@ if(BUILD_TESTING AND UNIX AND (OC_COMPILER_IS_GCC OR OC_COMPILER_IS_CLANG))
 endif()
 
 ######## Build configuration options ########
+set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+
 set(BUILD_EXAMPLE_APPLICATIONS ON CACHE BOOL "Build example applications.")
 set(BUILD_MBEDTLS ON CACHE BOOL "Build Mbed TLS library. When set to OFF, the Mbed TLS library with the OCF patches has to be provided.")
 set(BUILD_MBEDTLS_FORCE_3_5_0 OFF CACHE BOOL "Force v3.5.0 of the MbedTLS library to be used (by default v3.1.0 is used by master)")
@@ -57,15 +59,6 @@ set(OC_PUSH_ENABLED OFF CACHE BOOL "Enable Push Notification.")
 set(OC_PUSHDEBUG_ENABLED OFF CACHE BOOL "Enable debug messages for Push Notification.")
 set(OC_RESOURCE_ACCESS_IN_RFOTM_ENABLED OFF CACHE BOOL "Enable resource access in RFOTM.")
 set(OC_MEMORY_TRACE_ENABLED OFF CACHE BOOL "Enable memory tracing.")
-if (OC_DEBUG_ENABLED)
-    set(OC_LOG_MAXIMUM_LOG_LEVEL "TRACE" CACHE STRING "Maximum supported log level in compile time.")
-else()
-    set(OC_LOG_MAXIMUM_LOG_LEVEL "DISABLED" CACHE STRING "Maximum supported log level in compile time.")
-endif()
-set(OC_INOUT_BUFFER_SIZE "" CACHE STRING "Custom static buffer size for network messages.")
-set(OC_INOUT_BUFFER_POOL "" CACHE STRING "Custom static pool size of network messages.")
-set(OC_APP_DATA_BUFFER_SIZE "" CACHE STRING "Custom static buffer size for application messages.")
-set(OC_APP_DATA_BUFFER_POOL "" CACHE STRING "Custom static size of application messages.")
 set(OC_VERSION_1_1_0_ENABLED OFF CACHE BOOL "Enable OCF version 1.1")
 set(OC_ETAG_ENABLED OFF CACHE BOOL "Enable Entity Tag (ETag) support.")
 set(OC_JSON_ENCODER_ENABLED OFF CACHE BOOL "Enable JSON encoder/decoder support.")
@@ -75,7 +68,16 @@ if (BUILD_EXAMPLE_APPLICATIONS OR BUILD_TESTING)
 endif()
 set(PLGD_DEV_TIME_ENABLED OFF CACHE BOOL "Enable plgd time feature.")
 
-set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+if (OC_DEBUG_ENABLED)
+    set(OC_LOG_MAXIMUM_LOG_LEVEL "TRACE" CACHE STRING "Maximum supported log level in compile time.")
+else()
+    set(OC_LOG_MAXIMUM_LOG_LEVEL "DISABLED" CACHE STRING "Maximum supported log level in compile time.")
+endif()
+set(OC_INOUT_BUFFER_SIZE "" CACHE STRING "Custom static buffer size for network messages.")
+set(OC_INOUT_BUFFER_POOL "" CACHE STRING "Custom static pool size of network messages.")
+set(OC_APP_DATA_BUFFER_SIZE "" CACHE STRING "Custom static buffer size for application messages.")
+set(OC_APP_DATA_BUFFER_POOL "" CACHE STRING "Custom static size of application messages.")
+set(OC_DEVICE_MAX_NUM_CONCURRENT_REQUESTS "" CACHE STRING "Maximum number of messages in the network event queue for a device.")
 
 set(OC_ASAN_ENABLED OFF CACHE BOOL "Enable address sanitizer build.")
 set(OC_LSAN_ENABLED OFF CACHE BOOL "Enable leak sanitizer build.")
@@ -399,38 +401,6 @@ if(OC_MEMORY_TRACE_ENABLED)
     list(APPEND TEST_COMPILE_DEFINITIONS "OC_MEMORY_TRACE")
 endif()
 
-if (NOT("${OC_INOUT_BUFFER_SIZE}" STREQUAL ""))
-    if(NOT OC_DYNAMIC_ALLOCATION_ENABLED)
-        message(FATAL_ERROR "Cannot set custom static buffer size for network messages without dynamic allocation")
-    endif()
-    list(APPEND PUBLIC_COMPILE_DEFINITIONS "OC_INOUT_BUFFER_SIZE=(${OC_INOUT_BUFFER_SIZE})")
-    list(APPEND MBEDTLS_COMPILE_DEFINITIONS "OC_INOUT_BUFFER_SIZE=(${OC_INOUT_BUFFER_SIZE})")
-endif()
-
-if (NOT("${OC_INOUT_BUFFER_POOL}" STREQUAL ""))
-    if(NOT OC_DYNAMIC_ALLOCATION_ENABLED)
-        message(FATAL_ERROR "Cannot set custom static pool size for network messages without dynamic allocation")
-    endif()
-    list(APPEND PUBLIC_COMPILE_DEFINITIONS "OC_INOUT_BUFFER_POOL=(${OC_INOUT_BUFFER_POOL})")
-    list(APPEND MBEDTLS_COMPILE_DEFINITIONS "OC_INOUT_BUFFER_POOL=(${OC_INOUT_BUFFER_POOL})")
-endif()
-
-if (NOT("${OC_APP_DATA_BUFFER_SIZE}" STREQUAL ""))
-    if(NOT OC_DYNAMIC_ALLOCATION_ENABLED)
-        message(FATAL_ERROR "Cannot set custom static buffer size for application messages without dynamic allocation")
-    endif()
-    list(APPEND PUBLIC_COMPILE_DEFINITIONS "OC_APP_DATA_BUFFER_SIZE=(${OC_APP_DATA_BUFFER_SIZE})")
-    list(APPEND MBEDTLS_COMPILE_DEFINITIONS "OC_APP_DATA_BUFFER_SIZE=(${OC_APP_DATA_BUFFER_SIZE})")
-endif()
-
-if (NOT("${OC_APP_DATA_BUFFER_POOL}" STREQUAL ""))
-    if(NOT OC_DYNAMIC_ALLOCATION_ENABLED)
-        message(FATAL_ERROR "Cannot set custom static pool size for application messages without dynamic allocation")
-    endif()
-    list(APPEND PUBLIC_COMPILE_DEFINITIONS "OC_APP_DATA_BUFFER_POOL=(${OC_APP_DATA_BUFFER_POOL})")
-    list(APPEND MBEDTLS_COMPILE_DEFINITIONS "OC_APP_DATA_BUFFER_POOL=(${OC_APP_DATA_BUFFER_POOL})")
-endif()
-
 if(OC_VERSION_1_1_0_ENABLED)
     list(APPEND PUBLIC_COMPILE_DEFINITIONS "OC_SPEC_VER_OIC")
 endif()
@@ -454,6 +424,53 @@ if(PLGD_DEV_TIME_ENABLED)
     endif()
 endif()
 
+if(NOT("${OC_INOUT_BUFFER_SIZE}" STREQUAL ""))
+    if(NOT OC_DYNAMIC_ALLOCATION_ENABLED)
+        message(FATAL_ERROR "Cannot OC_INOUT_BUFFER_SIZE without dynamic allocation")
+    endif()
+    list(APPEND PUBLIC_COMPILE_DEFINITIONS "OC_INOUT_BUFFER_SIZE=(${OC_INOUT_BUFFER_SIZE})")
+    if(BUILD_MBEDTLS)
+        list(APPEND MBEDTLS_COMPILE_DEFINITIONS "OC_INOUT_BUFFER_SIZE=(${OC_INOUT_BUFFER_SIZE})")
+    endif()
+endif()
+
+if(NOT("${OC_INOUT_BUFFER_POOL}" STREQUAL ""))
+    if(NOT OC_DYNAMIC_ALLOCATION_ENABLED)
+        message(FATAL_ERROR "Cannot set OC_INOUT_BUFFER_POOL without dynamic allocation")
+    endif()
+    list(APPEND PUBLIC_COMPILE_DEFINITIONS "OC_INOUT_BUFFER_POOL=(${OC_INOUT_BUFFER_POOL})")
+    if(BUILD_MBEDTLS)
+        list(APPEND MBEDTLS_COMPILE_DEFINITIONS "OC_INOUT_BUFFER_POOL=(${OC_INOUT_BUFFER_POOL})")
+    endif()
+endif()
+
+if(NOT("${OC_APP_DATA_BUFFER_SIZE}" STREQUAL ""))
+    if(NOT OC_DYNAMIC_ALLOCATION_ENABLED)
+        message(FATAL_ERROR "Cannot set OC_APP_DATA_BUFFER_SIZE without dynamic allocation")
+    endif()
+    list(APPEND PUBLIC_COMPILE_DEFINITIONS "OC_APP_DATA_BUFFER_SIZE=(${OC_APP_DATA_BUFFER_SIZE})")
+    if(BUILD_MBEDTLS)
+        list(APPEND MBEDTLS_COMPILE_DEFINITIONS "OC_APP_DATA_BUFFER_SIZE=(${OC_APP_DATA_BUFFER_SIZE})")
+    endif()
+endif()
+
+if(NOT("${OC_APP_DATA_BUFFER_POOL}" STREQUAL ""))
+    if(NOT OC_DYNAMIC_ALLOCATION_ENABLED)
+        message(FATAL_ERROR "Cannot OC_APP_DATA_BUFFER_POOL without dynamic allocation")
+    endif()
+    list(APPEND PUBLIC_COMPILE_DEFINITIONS "OC_APP_DATA_BUFFER_POOL=(${OC_APP_DATA_BUFFER_POOL})")
+    if(BUILD_MBEDTLS)
+        list(APPEND MBEDTLS_COMPILE_DEFINITIONS "OC_APP_DATA_BUFFER_POOL=(${OC_APP_DATA_BUFFER_POOL})")
+    endif()
+endif()
+
+if(NOT("${OC_DEVICE_MAX_NUM_CONCURRENT_REQUESTS}" STREQUAL ""))
+    if(NOT OC_DYNAMIC_ALLOCATION_ENABLED)
+        message(FATAL_ERROR "Cannot set OC_DEVICE_MAX_NUM_CONCURRENT_REQUESTS without dynamic allocation")
+    endif()
+    list(APPEND PUBLIC_COMPILE_DEFINITIONS "OC_DEVICE_MAX_NUM_CONCURRENT_REQUESTS=(${OC_DEVICE_MAX_NUM_CONCURRENT_REQUESTS})")
+endif()
+
 if(BUILD_TESTING)
     list(APPEND PRIVATE_COMPILE_DEFINITIONS "OC_TEST")
     if(BUILD_MBEDTLS)

diff --git a/api/cloud/unittest/rd_client_test.cpp b/api/cloud/unittest/rd_client_test.cpp
@@ -215,7 +215,8 @@ TEST_F(TestRDClient, Publish_FailBadInput)
                           /*user_data*/ nullptr));
 }
 
-#if defined(OC_DYNAMIC_ALLOCATION) && !defined(OC_APP_DATA_BUFFER_SIZE)
+#if defined(OC_DYNAMIC_ALLOCATION) && !defined(OC_APP_DATA_BUFFER_SIZE) &&     \
+  !defined(OC_REP_ENCODING_REALLOC)
 
 TEST_F(TestRDClient, Publish_FailPayloadTooLarge)
 {
@@ -228,7 +229,8 @@ TEST_F(TestRDClient, Publish_FailPayloadTooLarge)
   oc_set_max_app_data_size(kDefaultSize);
 }
 
-#endif // OC_DYNAMIC_ALLOCATION && !OC_APP_DATA_BUFFER_SIZE
+#endif // OC_DYNAMIC_ALLOCATION && !OC_APP_DATA_BUFFER_SIZE &&
+       // !OC_REP_ENCODING_REALLOC
 
 #ifndef OC_DYNAMIC_ALLOCATION
 

diff --git a/api/oc_core_res.c b/api/oc_core_res.c
@@ -673,7 +673,7 @@ static bool
 core_is_resource_uri(const char *uri, size_t uri_len, const char *r_uri,
                      size_t r_uri_len)
 {
-  if (uri[0] == '/') {
+  if (uri_len > 0 && uri[0] == '/') {
     uri = &uri[1];
     --uri_len;
   }

diff --git a/api/oc_network_events.c b/api/oc_network_events.c
@@ -45,6 +45,37 @@ static bool g_interface_up;
 static bool g_interface_down;
 #endif /* OC_NETWORK_MONITOR */
 
+#ifdef OC_DYNAMIC_ALLOCATION
+static size_t
+get_events_queue_length(size_t device, oc_list_t events)
+{
+  size_t msg_count = 0;
+  for (oc_message_t *msg = (oc_message_t *)oc_list_head(events); msg != NULL;
+       msg = msg->next) {
+    if (msg->endpoint.device == device) {
+      ++msg_count;
+    }
+  }
+  return msg_count;
+}
+
+static void
+send_wakeup_signal(oc_list_t events)
+{
+  size_t msg_total = oc_list_length(events);
+
+  int deviceId = 0;
+  while (msg_total >= OC_DEVICE_MAX_NUM_CONCURRENT_REQUESTS) {
+    size_t msg_device_count = get_events_queue_length(deviceId, events);
+    if (msg_device_count >= OC_DEVICE_MAX_NUM_CONCURRENT_REQUESTS) {
+      oc_connectivity_wakeup(deviceId);
+    }
+    msg_total -= msg_device_count;
+    ++deviceId; // advance to the next device
+  }
+}
+#endif /* OC_DYNAMIC_ALLOCATION */
+
 static void
 oc_process_network_event(void)
 {
@@ -65,6 +96,11 @@ oc_process_network_event(void)
 #endif /* OC_NETWORK_MONITOR */
   oc_network_event_handler_mutex_unlock();
 
+#ifdef OC_DYNAMIC_ALLOCATION
+  // send a wake-up signal in case the queue might reach the limit for a device
+  send_wakeup_signal(network_events);
+#endif /* OC_DYNAMIC_ALLOCATION */
+
 #ifdef OC_HAS_FEATURE_TCP_ASYNC_CONNECT
   oc_tcp_on_connect_event_t *event =
     (oc_tcp_on_connect_event_t *)oc_list_pop(network_tcp_connect_events);
@@ -153,10 +189,10 @@ oc_network_tcp_connect_event(oc_tcp_on_connect_event_t *event)
 }
 #endif /* OC_HAS_FEATURE_TCP_ASYNC_CONNECT */
 
-int
+size_t
 oc_network_drop_receive_events(const oc_endpoint_t *endpoint)
 {
-  int dropped = 0;
+  size_t dropped = 0;
   oc_network_event_handler_mutex_lock();
   for (oc_message_t *message = (oc_message_t *)oc_list_head(g_network_events);
        message != NULL;) {
@@ -178,7 +214,20 @@ oc_network_drop_receive_events(const oc_endpoint_t *endpoint)
     }
     message = next;
   }
+
+#ifdef OC_DYNAMIC_ALLOCATION
+  size_t queue_len =
+    get_events_queue_length(endpoint->device, g_network_events);
+  // unlock mutex and send a wake-up signal in case the queue for the device was
+  // full
+  oc_network_event_handler_mutex_unlock();
+  if (queue_len + dropped >= OC_DEVICE_MAX_NUM_CONCURRENT_REQUESTS) {
+    oc_connectivity_wakeup(endpoint->device);
+  }
+#else
   oc_network_event_handler_mutex_unlock();
+#endif /* OC_DYNAMIC_ALLOCATION */
+
   return dropped;
 }
 
@@ -204,3 +253,14 @@ oc_network_interface_event(oc_interface_event_t event)
   _oc_signal_event_loop();
 }
 #endif /* OC_NETWORK_MONITOR */
+
+#ifdef OC_DYNAMIC_ALLOCATION
+size_t
+oc_network_get_event_queue_length(size_t device)
+{
+  oc_network_event_handler_mutex_lock();
+  size_t msg_count = get_events_queue_length(device, g_network_events);
+  oc_network_event_handler_mutex_unlock();
+  return msg_count;
+}
+#endif /* OC_DYNAMIC_ALLOCATION */
diff --git a/api/oc_network_events_internal.h b/api/oc_network_events_internal.h
@@ -58,7 +58,8 @@ void oc_network_tcp_connect_event(oc_tcp_on_connect_event_t *event)
  * @param endpoint the endpoint (cannot be NULL)
  * @return number of events dropped
  */
-int oc_network_drop_receive_events(const oc_endpoint_t *endpoint) OC_NONNULL();
+size_t oc_network_drop_receive_events(const oc_endpoint_t *endpoint)
+  OC_NONNULL();
 
 #ifdef OC_NETWORK_MONITOR
 /**
@@ -78,6 +79,14 @@ typedef struct oc_network_interface_cb
 void oc_network_interface_event(oc_interface_event_t event);
 #endif /* OC_NETWORK_MONITOR */
 
+/**
+ * @brief Returns the network event queue length for the device
+ *
+ * @param device valid device index
+ * @return number of events in the queue
+ */
+size_t oc_network_get_event_queue_length(size_t device);
+
 #ifdef __cplusplus
 }
 #endif

diff --git a/api/unittest/introspectiontest.cpp b/api/unittest/introspectiontest.cpp
@@ -199,6 +199,11 @@ TEST_F(TestIntrospectionWithServer, GetRequest)
 // the IDD data is too large for non-dynamic allocation and byte pool gets
 // exhausted
 
+#ifndef OC_REP_ENCODING_REALLOC
+
+// TODO: if the default application data size is too small, the introspection
+// data should realloc the buffer to sufficient size
+
 TEST_F(TestIntrospectionWithServer, GetDataRequest)
 {
   auto epOpt = oc::TestDevice::GetEndpoint(kDeviceID);
@@ -221,6 +226,8 @@ TEST_F(TestIntrospectionWithServer, GetDataRequest)
   EXPECT_TRUE(invoked);
 }
 
+#endif /* !OC_REP_ENCODING_REALLOC */
+
 TEST_F(TestIntrospectionWithServer, GetDataRequest_Fail)
 {
   oc::TestDevice::StopServer();