Receive CoAP Block messages on Thingy:53

RE: Receive CoAP Block messages on Thingy:53

Charlie — Mon, 05 Dec 2022 14:10:56 GMT

Hi Simon,

You can find a reference implementation of BlockwiseReceiveHook from openthread/cli_coap.cpp at main · openthread/openthread (github.com) or directly test with ot-cli commands sample,

remember to Updating pre-built OpenThread libraries with OPENTHREAD_CONFIG_COAP_BLOCKWISE_TRANSFER_ENABLE enabled, since this configuration is disabled by default.

Best regards,

Charlie

RE: Receive CoAP Block messages on Thingy:53

sihess — Sun, 04 Dec 2022 12:54:24 GMT

Hi, sorry for the late reply. Here some snippets of my code:

This is the request I send from the Thingy:53 device to the server:

static void get_request(struct k_work *item) {	
	
	ARG_UNUSED(item);

	otError 		error = OT_ERROR_NONE;
	otMessage 		*myMessage;
	otMessageInfo 	myMessageInfo;
	otInstance 		*myInstance = openthread_get_default_instance();
	
	LOG_INF("Send 'GET' request\n");

	do{
		myMessage = otCoapNewMessage(myInstance, NULL);
		if (myMessage == NULL) {
			printk("Failed to allocate message for CoAP Request\n");
			return;
		}
		memset(&myMessageInfo, 0, sizeof(myMessageInfo));
		myMessageInfo.mPeerPort = OT_DEFAULT_COAP_PORT;
		otIp6AddressFromString(serverAddr, &myMessageInfo.mPeerAddr);
		if (error != OT_ERROR_NONE){ 
			printk("IPv6 Error\n");
			break;
		}

    	otCoapMessageInit(myMessage, OT_COAP_TYPE_CONFIRMABLE, OT_COAP_CODE_GET);
    

		otCoapMessageGenerateToken(myMessage, OT_COAP_DEFAULT_TOKEN_LENGTH);
		error = otCoapMessageAppendObserveOption(myMessage, 0);
		if (error != OT_ERROR_NONE){ 
			printk("Append Observe Option Error\n");
    	}
    	
    	error = otCoapMessageAppendUriPathOptions(myMessage, "uri-path");
    	if (error != OT_ERROR_NONE){ 
    		printk("URI PATH FAIL\n");
    	}
    
    	error = otCoapMessageAppendContentFormatOption(myMessage, 
    										OT_COAP_OPTION_CONTENT_FORMAT_TEXT_PLAIN);
    	if (error != OT_ERROR_NONE){ 
    		printk("Content Error\n");
    	}
    	
    	error = otCoapMessageSetPayloadMarker(myMessage);
    	if (error != OT_ERROR_NONE){ 
    		printk("Set Payload Marker Error\n");
    	}
	
		if (error != OT_ERROR_NONE){ 
			printk("CoAP message initialization error!\n");
			break;
		}

		error = otCoapSendRequestBlockWise(myInstance, myMessage, &myMessageInfo,
											default_response_handler, NULL, NULL, BlockwiseReceiveHook);
	}
	while(false);

	if (error != OT_ERROR_NONE) {
		printk("Failed to send GET request: %d\n", error);
		otMessageFree(myMessage);
	}
	else{
		printk("GET request sent success");	
	}
}

And here the ReceiveHook function. This is currently just a test function to test if it even gets called:

otError BlockwiseReceiveHook(void         *aContext,
							const uint8_t *aBlock,
							uint32_t       aPosition,
							uint16_t       aBlockLength,
							bool           aMore,
							uint32_t       aTotalLength)
{
	printk("Receive Hook Function\n");

	OT_UNUSED_VARIABLE(aContext);
    OT_UNUSED_VARIABLE(aMore);
    OT_UNUSED_VARIABLE(aTotalLength);

    return OT_ERROR_NONE;
}

By using the debugger, I found out that the ReceiveHook gets called at the arrival of the message but then crashes somewhere in the code where the first block of the response gets handled.

I am able to receive the block response with this CoAP client browser plugin, so the server seems to be able to send it properly: https://github.com/mkovatsc/Copper

Thank you very much for your help!

Best wishes, Simon

RE: Receive CoAP Block messages on Thingy:53

ovrebekk — Thu, 17 Nov 2022 12:20:28 GMT

Hi Simon

Are you able to share your code so we can try to reproduce the issue here?

If you don't want to share your code in a public ticket I can make the case private.

Charlie is on travel this week, but he should be back next week.

Best regards
Torbjørn

RE: Receive CoAP Block messages on Thingy:53

sihess — Mon, 14 Nov 2022 13:25:57 GMT

Hi Charlie

Thanks for the fast reply. Yes, I already saw this post. The thing is however, that I try to receive a blockwise response from the server which is implemented with libcoap. This library provides a function that handles blockwise responses (https://libcoap.net/doc/reference/develop/man_coap_add_data_large_response.html#coap_add_data_large_response). I am able to receive the first block of 1024 bytes. But when I add the receive hook function in the request, the nrf device crashes as soon as the response arrives.

RE: Receive CoAP Block messages on Thingy:53

Charlie — Thu, 10 Nov 2022 09:47:17 GMT

Hi Simon,

There are some discussions about this topic on (+) Sending CoAP Block-wise requests (NCS 2.0.0) - Nordic Q&A - Nordic DevZone - Nordic DevZone (nordicsemi.com).

Let me know if this helps.

Best regards,

Charlie