ETag: Add CRC64 checksum for each stored resource

- Implemented the calculation of a CRC64 checksum for each resource
payload.
- By default, the GET payload with the "oic.if.baseline" interface
is used for a resource.
- Special handling is added for resources `/x.plgd.dev/time` and
`/oic/res`, which contain properties that might change on each GET
request. For these resources, an internal "x.plgd.if.etag"
interface is used to filter out problematic properties from the
payload.
- Updated the ETag storage payload to include not only the ETag
of the given resource but also the checksum for the resource.
- When data is loaded from storage, it now verifies the checksum
before processing, ensuring data integrity.

api/cloud/rd_client.c

@@ -43,7 +43,8 @@ _add_resource_payload(CborEncoder *parent, oc_resource_t *resource,
   oc_rep_start_object(parent, links);
   oc_rep_set_text_string(links, href, oc_string(resource->uri));
   oc_rep_set_string_array(links, rt, resource->types);
-  oc_core_encode_interfaces_mask(oc_rep_object(links), resource->interfaces);
+  oc_core_encode_interfaces_mask(oc_rep_object(links), resource->interfaces,
+                                 false);
   if (rel)
     oc_rep_set_text_string(links, rel, rel);
   oc_rep_set_int(links, ins, ins);

api/oc_collection.c

@@ -518,7 +518,7 @@ oc_handle_collection_create_request(oc_method_t method, oc_request_t *request)
                               oc_string_len(new_res->resource->uri));
     oc_rep_set_string_array(root, rt, new_res->resource->types);
     oc_core_encode_interfaces_mask(oc_rep_object(root),
-                                   new_res->resource->interfaces);
+                                   new_res->resource->interfaces, false);
     oc_rep_set_object(root, p);
     oc_rep_set_uint(p, bm, (uint8_t)(bm & ~(OC_PERIODIC | OC_SECURE)));
     oc_rep_close_object(root, p);
@@ -676,7 +676,8 @@ collection_encode_links(const oc_collection_t *collection,
     oc_rep_set_text_string_v1(links, href, oc_string(link->resource->uri),
                               oc_string_len(link->resource->uri));
     oc_rep_set_string_array(links, rt, link->resource->types);
-    oc_core_encode_interfaces_mask(oc_rep_object(links), link->interfaces);
+    oc_core_encode_interfaces_mask(oc_rep_object(links), link->interfaces,
+                                   false);
     oc_rep_set_string_array(links, rel, link->rel);
     oc_rep_set_int(links, ins, link->ins);
     oc_link_params_t *p = (oc_link_params_t *)oc_list_head(link->params);
@@ -814,7 +815,8 @@ oc_handle_collection_linked_list_request(oc_request_t *request)
       oc_rep_set_text_string_v1(links, href, oc_string(link->resource->uri),
                                 oc_string_len(link->resource->uri));
       oc_rep_set_string_array(links, rt, link->resource->types);
-      oc_core_encode_interfaces_mask(oc_rep_object(links), link->interfaces);
+      oc_core_encode_interfaces_mask(oc_rep_object(links), link->interfaces,
+                                     false);
       oc_rep_set_string_array(links, rel, link->rel);
       oc_rep_set_int(links, ins, link->ins);
       oc_link_params_t *p = (oc_link_params_t *)oc_list_head(link->params);

api/oc_core_res.c

@@ -164,7 +164,8 @@ oc_core_shutdown(void)
 }
 
 void
-oc_core_encode_interfaces_mask(CborEncoder *parent, unsigned iface_mask)
+oc_core_encode_interfaces_mask(CborEncoder *parent, unsigned iface_mask,
+                               bool include_private)
 {
   oc_rep_set_key((parent), "if");
   oc_rep_start_array((parent), if);
@@ -201,6 +202,13 @@ oc_core_encode_interfaces_mask(CborEncoder *parent, unsigned iface_mask)
   if ((iface_mask & OC_IF_STARTUP_REVERT) != 0) {
     oc_rep_add_text_string(if, OC_IF_STARTUP_REVERT_STR);
   }
+#ifdef OC_HAS_FEATURE_ETAG_INTERFACE
+  if (include_private && (iface_mask & PLGD_IF_ETAG) != 0) {
+    oc_rep_add_text_string(if, PLGD_IF_ETAG_STR);
+  }
+#else  /* OC_HAS_FEATURE_ETAG_INTERFACE */
+  (void)include_private;
+#endif /* OC_HAS_FEATURE_ETAG_INTERFACE */
   oc_rep_end_array((parent), if);
 }
 

api/oc_core_res_internal.h

@@ -71,9 +71,10 @@ oc_device_info_t *oc_core_add_new_device(oc_add_new_device_t cfg);
  *
  * @param parent the cbor encoder (cannot be NULL)
  * @param iface_mask the interfaces (as bit mask)
+ * @param include_private include private interfaces
  */
-void oc_core_encode_interfaces_mask(CborEncoder *parent, unsigned iface_mask)
-  OC_NONNULL();
+void oc_core_encode_interfaces_mask(CborEncoder *parent, unsigned iface_mask,
+                                    bool include_private) OC_NONNULL();
 
 /**
  * @brief store the uri as a string