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net: lwm2m: fix observation path list ordering

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under certain conditions the current implementation did not maintain
the desired sort order.

Signed-off-by: Pascal Brogle <pascal.brogle@husqvarnagroup.com>
This commit is contained in:
Pascal Brogle 2022-12-08 15:54:50 +01:00 • committed by Carles Cufí
commit 6ac281887c
6 changed files with 639 additions and 36 deletions
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94
subsys/net/lib/lwm2m/lwm2m_observation.c
View file

@ -1499,7 +1499,9 @@ int lwm2m_engine_add_path_to_list(sys_slist_t *lwm2m_path_list, sys_slist_t *lwm
new_entry->path = *path;
if (!sys_slist_is_empty(lwm2m_path_list)) {
/* Keep list Ordered by Object ID/ Object instance/ resource ID */
/* Keep list Ordered by Object ID / Object instance / resource ID /
* Resource Instance ID
*/
SYS_SLIST_FOR_EACH_CONTAINER(lwm2m_path_list, entry, node) {
if (entry->path.level == LWM2M_PATH_LEVEL_NONE ||
lwm2m_obj_path_equal(&entry->path, &new_entry->path)) {
@ -1508,39 +1510,63 @@ int lwm2m_engine_add_path_to_list(sys_slist_t *lwm2m_path_list, sys_slist_t *lwm
return 0;
}
if (entry->path.obj_id > path->obj_id) {
/* New entry have smaller Object ID */
add_before_current = true;
} else if (entry->path.obj_id == path->obj_id &&
entry->path.level > path->level) {
add_before_current = true;
} else if (entry->path.obj_id == path->obj_id &&
entry->path.level == path->level) {
if (path->level >= LWM2M_PATH_LEVEL_OBJECT_INST &&
entry->path.obj_inst_id > path->obj_inst_id) {
/*
* New have same Object ID
* but smaller Object Instance ID
*/
add_before_current = true;
} else if (path->level >= LWM2M_PATH_LEVEL_RESOURCE &&
entry->path.obj_inst_id == path->obj_inst_id &&
entry->path.res_id > path->res_id) {
/*
* Object ID and Object Instance id same
* but Resource ID is smaller
*/
add_before_current = true;
} else if (path->level >= LWM2M_PATH_LEVEL_RESOURCE_INST &&
entry->path.obj_inst_id == path->obj_inst_id &&
entry->path.res_id == path->res_id &&
entry->path.res_inst_id > path->res_inst_id) {
/*
* Object ID, Object Instance id & Resource ID same
* but Resource instance ID is smaller
*/
add_before_current = true;
}
/*
* algorithm assumes that list is already properly sorted and that
* there are no duplicates. general idea:
* - if at any level up to new entry's path level, IDs below the level
* match and the ID of the new entry at that level is smaller,
* insert before.
* - if all IDs of the new entry match the existing entry, insert before.
* Because of sorting and no duplicates, the existing entry must have
* higher path level and come after the new entry.
*/
switch (new_entry->path.level) {
case LWM2M_PATH_LEVEL_OBJECT:
add_before_current = new_entry->path.obj_id <= entry->path.obj_id;
break;
case LWM2M_PATH_LEVEL_OBJECT_INST:
add_before_current =
(new_entry->path.obj_id < entry->path.obj_id) ||
(entry->path.level >= LWM2M_PATH_LEVEL_OBJECT_INST &&
entry->path.obj_id == new_entry->path.obj_id &&
new_entry->path.obj_inst_id <= entry->path.obj_inst_id);
break;
case LWM2M_PATH_LEVEL_RESOURCE:
add_before_current =
(new_entry->path.obj_id < entry->path.obj_id) ||
(entry->path.level >= LWM2M_PATH_LEVEL_OBJECT_INST &&
entry->path.obj_id == new_entry->path.obj_id &&
new_entry->path.obj_inst_id < entry->path.obj_inst_id) ||
(entry->path.level >= LWM2M_PATH_LEVEL_RESOURCE &&
entry->path.obj_id == new_entry->path.obj_id &&
entry->path.obj_inst_id == new_entry->path.obj_inst_id &&
new_entry->path.res_id <= entry->path.res_id);
break;
case LWM2M_PATH_LEVEL_RESOURCE_INST:
add_before_current =
(new_entry->path.obj_id < entry->path.obj_id) ||
(entry->path.level >= LWM2M_PATH_LEVEL_OBJECT_INST &&
entry->path.obj_id == new_entry->path.obj_id &&
new_entry->path.obj_inst_id < entry->path.obj_inst_id) ||
(entry->path.level >= LWM2M_PATH_LEVEL_RESOURCE &&
entry->path.obj_id == new_entry->path.obj_id &&
entry->path.obj_inst_id == new_entry->path.obj_inst_id &&
new_entry->path.res_id < entry->path.res_id) ||
(entry->path.level >= LWM2M_PATH_LEVEL_RESOURCE_INST &&
entry->path.obj_id == new_entry->path.obj_id &&
entry->path.obj_inst_id == new_entry->path.obj_inst_id &&
entry->path.res_id == new_entry->path.res_id &&
new_entry->path.res_inst_id <= entry->path.res_inst_id);
break;
}
if (add_before_current) {

20
subsys/net/lib/lwm2m/lwm2m_observation.h
View file

@ -61,13 +61,29 @@ struct lwm2m_obj_path_list {
void lwm2m_engine_path_list_init(sys_slist_t *lwm2m_path_list, sys_slist_t *lwm2m_free_list,
struct lwm2m_obj_path_list path_object_buf[],
uint8_t path_object_size);
/* Add new Path to the list */
/**
* Add new path to the list while maintaining hierarchical sort order
*
* @param lwm2m_path_list sorted path list
* @param lwm2m_free_list free list
* @param path path to be added
* @return 0 on success or a negative error code
*/
int lwm2m_engine_add_path_to_list(sys_slist_t *lwm2m_path_list, sys_slist_t *lwm2m_free_list,
struct lwm2m_obj_path *path);
int lwm2m_get_path_reference_ptr(struct lwm2m_engine_obj *obj, struct lwm2m_obj_path *path,
void **ref);
/* Remove paths when parent already exist in the list. */
/**
* Remove paths when parent already exists in the list
*
* @note Path list must be sorted
* @see lwm2m_engine_add_path_to_list()
*
* @param lwm2m_path_list sorted path list
* @param lwm2m_free_list free list
*/
void lwm2m_engine_clear_duplicate_path(sys_slist_t *lwm2m_path_list, sys_slist_t *lwm2m_free_list);
/* Resources */