Read / Write lwm2m resource instance

RE: Read / Write lwm2m resource instance

Charlie — Thu, 18 Nov 2021 14:55:50 GMT

Hi ICM_UC,

Looks like the source codes of lwm2m_enngine.c is from zephyr/lwm2m_engine.c at main · zephyrproject-rtos/zephyr (github.com).

I think it would be better you create one issue report and proposal your solution to the Zephyr GitHub repository. It is a great honor to contribute to such a project. 😉

Best regards,

Charlie

RE: Read / Write lwm2m resource instance

ICM_UC — Wed, 17 Nov 2021 15:43:00 GMT

Hi Charlie,

The changes in order to read a specific resource instance are minor.

In the file 'lwm2m_engine.c' function 'lwm2m_read_handler'

Need to change 2 thing

first <> from this

for (i = 0; i < loop_max; i++) {
		if (res->res_instances[i].res_inst_id ==
		    RES_INSTANCE_NOT_CREATED) {
			continue;
		}

		if (res->res_inst_count > 1) {
			msg->path.res_inst_id =
				res->res_instances[i].res_inst_id;
		}

		/* setup initial data elements */
		data_ptr = res->res_instances[i].data_ptr;
		data_len = res->res_instances[i].data_len;

to this

for (i = 0; i < loop_max; i++) {
		if (res->res_instances[i].res_inst_id ==
		    RES_INSTANCE_NOT_CREATED) {
			continue;
		}

		if (res->res_inst_count > 1) {
            if ((msg->path.level > 3U) && 
                (res->res_instances[i].res_inst_id != msg->path.res_inst_id)) {
                continue;
            }
			msg->path.res_inst_id =
				res->res_instances[i].res_inst_id;
		}

		/* setup initial data elements */
		data_ptr = res->res_instances[i].data_ptr;
		data_len = res->res_instances[i].data_len;

second <> From this

    if (res->multi_res_inst) {
        engine_put_end_ri(&msg->out, &msg->path);
		msg->path.res_inst_id = res_inst_id_tmp;
	}

	return 0;
}

    if (res->multi_res_inst) {
        if (msg->path.level < 4U) {
          engine_put_end_ri(&msg->out, &msg->path);
        }
		msg->path.res_inst_id = res_inst_id_tmp;
	}

	return 0;
}

RE: Read / Write lwm2m resource instance

ICM_UC — Wed, 17 Nov 2021 12:06:17 GMT

Hi Charlie,

Yes, the same happens to objects in LwM2M Client sample.

I'm working on the changes needed to support Read/Write resource instances and then i'll post them here

RE: Read / Write lwm2m resource instance

Charlie — Tue, 16 Nov 2021 15:35:58 GMT

Hi ICM_UC,

You can share your modification to the lwm2m library here. I will create an internal bug or improvement report after evaluating your solution.

Do you experience a similar issue with objects in the current nRF9160: LwM2M Client sample?

Best regards,

Charlie

RE: Read / Write lwm2m resource instance

ICM_UC — Tue, 16 Nov 2021 14:50:41 GMT

Hi Charlie,

I still need your help!

To correct this problem i need to change nordic lwm2m library and this is a problem because every time you update SDK i need to replicate all the changes.

How can we solve this problem?

RE: Read / Write lwm2m resource instance

Charlie — Tue, 16 Nov 2021 14:46:43 GMT

Hi ICM_UC,

Sorry for my misunderstanding, glad to hear you found the issue.

Best regards,

Charlie

RE: Read / Write lwm2m resource instance

ICM_UC — Tue, 16 Nov 2021 14:18:46 GMT

After digging in other blogs i found what should be the answer for 'Read resource instance'

This is what Leshan asks

00> >>>> RCV COAP MSG LEN: 26<<<<
00>
00> Header<> 48 01 #ID 07 7a #TK 78 62 70 15 7e de ef 47
00> Payld <> b3 35 30 34 01 30 02 31 31 01 30 62 2d 16
00> >>>> END MSG <<<<
00>
00> RCV PATH: obj_id 504, obj_inst_id 0, res_id 11, res_inst_id 0, level 4
00>

This should be what lwm2m client answers

00> >>>> SND COAP MSG LEN: 39<<<<
00>
00> Header<> 68 45 #ID 07 7a #TK 78 62 70 15 7e de ef 47
00> Payld <> c2 2d 16 ff 48 00 14 38 39 33 35 31 30 36 30 30 30 30 37 37 30 38 36 32 39 39 31
00> >>>> END MSG <<<<

With this answer from lwm2m client everything works fine.

RE: Read / Write lwm2m resource instance

ICM_UC — Tue, 16 Nov 2021 14:09:25 GMT

Hi Charlie,

You are missing the point. My problem is not the info inside that resource instance, that is a string and i can force any value there, what i need is to resolve the problem explained in the first post. If i read the resource, everything is OK, but if i read the resource instance i get an error.

After exploring more the code i realized that Leshan sends a different payload depending on the button pressed, read resource or resource instance, but the answer from LWm2m client is the same.

This is what Leshan send when we press 'Read resource'

>>>> RCV COAP MSG LEN: 24<<<<
00> Header<> 48 01 #ID 07 79 #TK dc ae 4e 38 b6 5c 1b 33
00> Payld <> b3 35 30 34 01 30 02 31 31 62 2d 16
00> >>>> END MSG <<<<

00> RCV PATH: obj_id 504, obj_inst_id 0, res_id 11, res_inst_id 0, level 3
This is what lwm2m client answers

>>>> SND COAP MSG LEN: 42<<<<
00> Header<> 68 45 #ID 07 79 #TK dc ae 4e 38 b6 5c 1b 33
00> Payld <> c2 2d 16 ff 88 0b 17 48 00 14 38 39 33 35 31 30 36 30 30 30 30 37 37 30 38 36 32 39 39 31
>>>> END MSG <<<<

Until here everything is OK. The problem cames when i press 'Read resource instance'. see the payload

>>>> RCV COAP MSG LEN: 26<<<<
00> Header<> 48 01 #ID 07 7a #TK 78 62 70 15 7e de ef 47
00> Payld <> b3 35 30 34 01 30 02 31 31 01 30 62 2d 16
00> >>>> END MSG <<<<

00> RCV PATH: obj_id 504, obj_inst_id 0, res_id 11, res_inst_id 0, level 4

00> >>>> SND COAP MSG LEN: 39<<<<
00> Header<> 68 45 #ID 07 7a #TK 78 62 70 15 7e de ef 47
00> Payld <> c2 2d 16 ff 88 0b 17 48 00 14 38 39 33 35 31 30 36 30 30 30 30 37 37 30 38 36 32 39 39 31
00> >>>> END MSG <<<<

RE: Read / Write lwm2m resource instance

Charlie — Tue, 16 Nov 2021 13:39:01 GMT

Hi ICM_UC,

After some investigation, I do not think Nordic as the SoC producer can help you debug this issue. We can only provide your samples about how to write the implements for one lwm2m object. As Remote SIM provisioning Wikipedia explains, this is an eSIM speciation realized by GSMA. You need to check with your SIM card provider to see if this is supported by their products, or as a SIM card provider you need internal cooperation to find the cause of the issue.

Where did you get those codes? Can you get help from the provider? If you are a SIM card solution provider, please give us more background knowledge about your project. You can contact our local sales team to get more suggestions about your development.

Best regards,

Charlie

RE: Read / Write lwm2m resource instance

ICM_UC — Thu, 11 Nov 2021 16:09:21 GMT

Hi Charlie,

I searched the code to see how the objects are created and replicated that for this object

/* LWM2M object variables */
static struct lwm2m_engine_obj remote_sim_provisioning;

static struct lwm2m_engine_obj_field remote_sim_provisioning_fields[] = {
	OBJ_FIELD_DATA(LWM2M_REMOTE_SIM_PROVISIONING_ICCID_ID, R, STRING),
};

After this, inicialized the object

static int 
UC_LWM2M_Remote_SIM_Provisioning_Init(const struct device *dev)
{
	/* Declare unused arguments */
	ARG_UNUSED(dev);
	
	/* Create and register LwM2M object type */
	remote_sim_provisioning.obj_id = LWM2M_REMOTE_SIM_PROVISIONING_ID;
	remote_sim_provisioning.version_major = LWM2M_PROTOCOL_VERSION_MAJOR;
	remote_sim_provisioning.version_minor = LWM2M_PROTOCOL_VERSION_MINOR;
	remote_sim_provisioning.is_core = true;
	remote_sim_provisioning.fields = remote_sim_provisioning_fields;
	remote_sim_provisioning.field_count = ARRAY_SIZE(remote_sim_provisioning_fields);
	remote_sim_provisioning.max_instance_count = LWM2M_REMOTE_SIM_PROVISIONING_INSTANCE_COUNT;
	remote_sim_provisioning.create_cb = UC_LWM2M_Remote_SIM_Provisioning_Create;
	lwm2m_register_obj(&remote_sim_provisioning);

	return NRF_SUCCESS;
}

/* Initialiase LWM2M object type */
SYS_INIT(UC_LWM2M_Remote_SIM_Provisioning_Init, APPLICATION, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT);

and this function is called when an instance is created

static struct lwm2m_engine_obj_inst*
UC_LWM2M_Remote_SIM_Provisioning_Create(uint16_t obj_inst_id)
{
	/* Initialise function variables */
	int index, i = 0, j = 0;
	
	/* Only allow the default instance ID to be created */
	if (LWM2M_REMOTE_SIM_PROVISIONING_DEFAULT_INSTANCE != obj_inst_id) {
		LOG_ERR("Can not create instance %u for this object", obj_inst_id);
		return NULL;
	}

	/* Check that there is no other instance with this ID */
	for (index = 0; index < LWM2M_REMOTE_SIM_PROVISIONING_INSTANCE_COUNT; index++) {
		if (inst[index].obj && inst[index].obj_inst_id == obj_inst_id) {
			LOG_ERR("Can not create instance - already existing: %u", obj_inst_id);
			return NULL;
		}
	}
	
	
	/* Check if the maximum number of instances hasn't been reached */
	if (index >= LWM2M_REMOTE_SIM_PROVISIONING_INSTANCE_COUNT) {
		LOG_ERR("Can not create instance - no more room: %u", obj_inst_id);
		return NULL;
	}

	/* Set default resource values */
	memset(iccid[index], 0, ICCID_STRING_LENGTH);
	
	/* Zero-initialiase instance resource object */
	(void)memset(res[index], 0, sizeof(res[index][0]) * ARRAY_SIZE(res[index]));
	init_res_instance(res_inst[index], ARRAY_SIZE(res_inst[index]));

	/* Initialise resource instance data */
	INIT_OBJ_RES_MULTI_DATA(LWM2M_REMOTE_SIM_PROVISIONING_ICCID_ID, res[index], i, res_inst[index], j,
                LWM2M_REMOTE_SIM_PROVISIONING_ICCID_INSTANCE_COUNT, true,
		        &iccid[index], ICCID_STRING_LENGTH);

                
	inst[index].resources = res[index];
	inst[index].resource_count = i;
	
	LOG_DBG("Created LwM2M Remote SIM Provisioning instance: %d", obj_inst_id);
	
	return &inst[index];
}

After all this, when connected to Leshan, a function is called to inicialize the object and resorce instance

static void
UC_LWM2M_Remote_SIM_Provisioning_InitInstance(struct k_work *work) {

...

    return_code = lwm2m_engine_create_obj_inst(LWM2M_REMOTE_SIM_PROVISIONING_INSTANCE);	
    		
    /* Register callbacks only if the instance was successfully created */
    if (NRF_SUCCESS == return_code || -EEXIST == return_code || -ENOMEM == return_code) {
        for (int idx = 0; idx < LWM2M_REMOTE_SIM_PROVISIONING_ICCID_INSTANCE_COUNT; idx++) {
            /* Generate the resource path being read */
            sprintf((char*)remote_sim_provisioning_resource_path,
                    LWM2M_REMOTE_SIM_PROVISIONING_INSTANCE_CUSTOM_RESOURCE_TEMPLATE, LWM2M_REMOTE_SIM_PROVISIONING_ICCID_ID, idx);
            
            return_code += lwm2m_engine_create_res_inst(remote_sim_provisioning_resource_path);
            
            return_code += 
            lwm2m_engine_register_read_callback(remote_sim_provisioning_resource_path, 
                                                  UC_LWM2M_Remote_SIM_Provisioning_ReadCallback);
        }
	
		/* Trigger update so that the server is immediately notified of the new instance */
		engine_trigger_update(true);
		
		if (NRF_SUCCESS == return_code) {
			LOG_DBG("Init OK: LwM2M Remote SIM Provisioning %u", 
				LWM2M_REMOTE_SIM_PROVISIONING_DEFAULT_INSTANCE);
				return;
		}
	}
}

At this point when i go to Leshan server i have the problem explained on the firt post

RE: Read / Write lwm2m resource instance

Charlie — Thu, 11 Nov 2021 15:47:46 GMT

Hi ICM_UC,

Yes, but your lwm2m client needs to add support for the object, then it can be checked on the lwm2m server.

How did you modify the nRF9160: LwM2M Client to add this object?

Best regards,

Charlie

RE: Read / Write lwm2m resource instance

ICM_UC — Wed, 10 Nov 2021 10:20:51 GMT

Hi Charlie,

Thank for your concern but this object is public as you can confirm on the link below.

Open Mobile Alliance - LwM2M Registry

Lets keep this public to help others in the same situation

RE: Read / Write lwm2m resource instance

Charlie — Wed, 10 Nov 2021 09:59:01 GMT

Hi ICM_UC,

There is no ‘Remote SIM Provisioning’ object 504 in the current nRF9160: LwM2M Client sample, have you added your own implementation on it? I can set this ticket to private if you only want to share it only with us.

Best regards,

Charlie